Answer:
B "To muse"
Step-by-step explanation:
Infinitives are illustrated as the basic form of the verb that functions to link the verb to the subject or tense without any modulation. It always begins with the preposition 'to' and functions as an adjective, adverb, direct or indirect object or to answer the questions like when, where, etc.
As per the question, the infinitive in the given sentence would be 'to muse' as the preposition 'to' followed here only by the basic verb 'muse'. The rest of the times 'to' is followed by a noun and therefore, fails to categorize as an infinitive. Thus, 'to muse', is the infinitive in the given sentence and hence, option B is the answer.