Answer:
D. The three astronauts genuinely enjoyed the flight.
Step-by-step explanation:
A direct object is a noun or a pronoun that receives the main action of a sentence; We can identify direct objects by asking ourselves the “what?” or the “who?” questions. In sentence D, the noun “flight” is receiving the action “enjoyed,” thus, it is the direct object. If any doubts, it also provides the answer to the question “What did the three astronauts genuinely enjoyed?” A: the flight.