Read the sentence. the teenagers went to town to muse over whether going to college or to university was the better choice. which part of the sentence is an infinitive?

'to muse' is the infinitive. To spot an infinitive just look for the word 'to' and a verb that justifies its use for the purpose of doing something. Such as "to muse" would mean that the teenagers went to town to think about which was the best choice.