Which sentence uses a infinitive phrase as a modifier?
a) do you want to pass my class with the least amount of effort possible?
b) on the camping trip, all of the women gathered firewood for the first night.
c) the best way to cook a grilled cheese is with a strip of bacon in the middle.
d) the people who designed the scavenger hunt made it more difficult than necessary.

The sentence that uses a infinitive phrase as a modifier is option C. The best way to cook a grilled cheese is with a strip of bacon in the middle.

An infinitive phrase is the infinitive form of a verb plus any complements and modifiers.  The infinitive phrase can be a subject, an adjective, an adverb, a direct object, or a predicate nominative in a sentence.  In the case of and adjective it tends to modify a noun placed before.

to save the day, harry must get past a scary three-headed guard dog.

the answer should be the first one. "many people find his lyrics very moving."

it by far makes the most grammatical sense and is very objective, removing any first person from the original sentence and keeping with the sentence fluency.