Answer:
D) He had dreamed about the Great Wall of China long before he visited it.
Step-by-step explanation:
A: "Last night, he dreamed about visiting the Great Wall of China" is incorrect because it uses the term "visiting" which is not perfect past tense
B: "Again this evening, he will be dreaming of the Great Wall of China" is incorrect because it is not written in the past tense whatsoever. It is foreshadowing the future.
C: "He dreams about visiting the Great Wall of China one day" is written in the present tense.