Detailed Solution
The correct answer is- The ending of the play surprised the audience.
Additional Information
The given sentence is in a passive voice form, hence we need to convert it into an active voice form.
Find the subject (The audience) and object (the ending of the play) of the sentence and exchange their places.
The given sentence is in the simple past tense.
The active verb form for simple past is: Subject + past participle form of the verb + Object.
So, 'was surprised' changes to 'surprised'. At last line up the remaining part.
Following these steps, we finally get- The ending of the play surprised the audience.

The correct answer is The police refused them entry in Delhi.
Key Points
The given sentence is in the Passive Voice.
As per the given question we have to change the sentence into Active Form.
The structure of the given sentence as follows: Subject+V2+Object.
(Active Voice) Subject (objective case)+was/were+V3+Object (subjective case).
(Passive Voice) 'Were refused' will be changed into 'refused'.
'They' will be changed into 'them'.

The given sentence is in an active voice form, hence we need to convert it into a passive voice form.
Find the subject (Our team) and object (350 runs) of the sentence and exchange their places.
The given sentence is in the simple past tense.
The passive verb form for simple past is: was/were + past participle form of the verb.
So, 'scored' changes to 'were scored'. At last line up the remaining part.
Following these steps, we finally get- 350 runs were scored by our team in the Inter-college Cricket Tournament.

In Active Voice, a sentence emphasizes the subject, performing an action.
In Passive Voice, a sentence emphasizes the action or the object of the sentence.
The given sentence is in the passive voice and 'all his faults' is the subject and 'her' is the object.
When we convert this sentence into active voice, the subject 'all his faults' of the passive voice becomes the object, the object 'her' becomes the subject 'she'.
The passive format "were + V3 (forgiven)" should be changed into the active format "V2 (forgave)".
This is the active and passive voice rule for the past simple tense.

In Active Voice, a sentence emphasizes the subject, performing an action.
In Passive Voice, a sentence emphasizes the action or the object of the sentence.
The given sentence is in the active voice and 'Razia Sultana' is the subject and 'the northern part of India' is the object.
When we convert this sentence into passive voice, the subject 'Razia Sultana' of the active voice becomes the object, the object 'the northern part of India' becomes the subject.
The passive format "was + V3 (ruled)" should be used.
This is the active and passive voice rule for the past simple tense.
Hence, the correct sentence is 'The northern part of India was ruled over by Razia Sultana'

The given sentence is in a passive voice form, hence we need to convert it into an active voice form.
We need to follow these instructions while changing the voice of an interrogative sentence.
The inverted form of the verb i.e. Did you leave, will commence the sentence.
The given sentence is in the simple past tense.
The active voice form for the simple past interrogative sentence:
Helping verb (Did) + subject + V1 + object? At last line up the remaining part.
Following these steps, we finally get- Did you leave your bag in the bus?

The given sentence is an example of Active Voice. As per the given question, we have to change it to Passive Voice.
The process of transformation is as follows:
The subject of the given sentence is 'They'.
The object of the given sentence is 'Elaborate'.
The subject will be put in place of the object and the object will be put in place of the subject.
'Are making' will be changed into 'are being made'.
However, the subject 'they' will not be used as 'by them' because it becomes the hidden subject here. This is so because here the action is the central focus and the actor can be any unknown/general entity.
Thus the correct sentence is: Elaborate arrangements are being made for the party.

Some nouns are not made plural by adding 's/es'. It is done in a different manner.
Criterion- criteria, mouse- mice, phenomenon- phenomena, radius- radii, syllabus- syllabi, etc.
For example: You don't fulfill the criterions set by the commission.(wrong)
You don't fulfill the criteria set by the commission.(Right)
We need the plural form of the given noun in the sentence i.e. mice.