I believe it’s sometimes because it describes an adjective
Answer:
B, "is situated"
Explanation:
Process of elimination:
A: The Oval Office is in the White House today, so the sentence should not be in the past tense.
C: This is not grammatically correct. The sentence needs a verb of a tense of "to be" like "is" or "was".
D: This is not grammatically correct. The sentence needs a verb of a tense of "to be" like "is" or "was". Also, since the Oval Office is singular, the word would be situates instead of situate anyway.
It is true that the expressionist described the world outside the character through the character's moods and impressions.