Answer : 4. "Adverb"
Explanation :

To determine the part of speech of the underlined word "quickly," we need to understand its role in the sentence.

• Noun: A noun is a word that names a person, place, thing, or idea. "Quickly" does not name anything.
• Adjective: An adjective describes or modifies a noun or pronoun. "Quickly" does not describe a noun.
• Verb: A verb expresses an action or state of being. The main verb in this sentence is "ran."
• Adverb: An adverb modifies a verb, adjective, or another adverb, often indicating how, when, where, or to what extent something is done. "Quickly" describes how she ran.

In this sentence, "quickly" modifies the verb "ran," indicating how she ran.

Therefore, the correct answer is:

d) Adverb