Final answer:
The sentence with an infinitive functioning as a direct object is 'The team of fire inspectors decided to stay.' In this sentence, 'to stay' directly receives the action of the verb 'decided.'
Step-by-step explanation:
The question asks to identify which sentence contains an infinitive functioning as a direct object. An infinitive is the basic form of a verb, usually preceded by 'to.'
For example, 'to run,' 'to eat,' and 'to speak' are infinitives. In grammar, a direct object is a noun or pronoun that receives the action of a verb.
The correct answer to the question is: The team of fire inspectors decided to stay. In this sentence, 'to stay' is the infinitive and it is acting as the direct object because it is what the fire inspectors decided to do.
It receives the action of the verb 'decided' without the intervention of any other element.
Other sentences contain infinitives as well, but they do not function as direct objects. It is crucial to note that an infinitive acting as a direct object directly receives the action of the verb without any intermediary.