Which of the following should be avoided in official letter?

Choose the correct option:
 When we begin a letter with 'Dear Sir' or 'Dear Madam' or 'Dear Sir/Madam', we end it with____

Choose the correct option:
 Notices should be

Choose the appropriate article given in the options:
 Neil Armstong was ______ fast man to walk on the moon.

Choose the correct exclamatory form of the following sentence from the options. given below:
I wish I were a clown.

Choose the correct transformation from assertive to exclamatory:
I wish I knew more people.

Change from assertive to exclamatory.
The sunrise is very beautiful.

Choose the correct assertive form of the following sentence from the options given below:
How attractive the picture is!