The sentence that contains a boldface infinitive is D. Lisa wants TO GO.
It is easy to spot an infinitive - it is usually a combination of the word TO plus a verb.
A and C are incorrect because those are not infinitives, but rather prepositional phrases. B is incorrect because it is an infinitival phrase, rather than a single infinitive.
A
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I had a teacher once tell me allot of times the summary will be in the first sentence and sometimes it may be in the last
Doesn't he think that he hears the heart beating under the floor board?
Because he hears this faint beating leaving him to be paranoid that the cops know that he hid that guy under there.