Which part of the sentence is an infinitive?
the teenagers went to town to muse over whether going to college or to university was the better choice.
a) to town
b) to muse
c) to college
d) to university

B) To muse.

Explanation: an infinitive verb is a verb with the word "to" in front of it, and that can act as a noun, an adjective or an adverb. When we use an infinitive verb, "to" is a part of the verb and not a preposition. In the given sentence, the example of infinitive is "to muse" because "muse" is a verb. The phrases "to town", "to college" and "to university" aren't infinitive because they are not verbs, they are prepositional phrases.

B) to muse

An infinitive is a phrase that will have the word “to” followed by a verb.  When we look at the possible answers for this question, the words “town,” “muse,” “college,” and “university.”  At first glance all of the words appear to be nouns.  However, “muse” can actually serve as both a noun and a verb, which is why this question was a bit tricky.  As a noun, “muse” can mean a poet or one inspiring an artist.  As a verb, “muse” can mean to think/ponder.  If “muse” is serving as a verb, then, yes, the phrase “to muse” would be an infinitive.  

if you don't mind posting the paragraph so i could read it that would a lot. (;

very interesting story but where is the question what is actually a question i don't understand