Question

wistful (adj.)
feeling or showing no emotion
vague or regretful longing
not habitual, or ordinary
brought under control; made less intense

Explanation:

"Wistful" is an adjective defined as having or showing a vague or regretful longing for something, often something in the past that cannot be changed or regained. The other options do not match this definition: the first describes apathy, the third describes something unusual, and the fourth describes something subdued or controlled.

Answer:

B. vague or regretful longing