Answer:
The answer is A.
Step-by-step explanation:
Infinitive is a non-finite verb form (verb forms that do not have person, tense or number). It can function as a noun, adjective or adverb.
For example: to sing
Direct object is a word or a phrase which receives the action of the subject or it is under the influence of it. Generally it comes after a verb (without preposition).
For example: She made a cake.
Considering that direct object comes after a verb, in only one example we see that kind of construction and that is the answer A.