The correct answer is D. flippant.
A facetious remark is one that is made in a light-hearted or joking way, but which may also be intended to be insulting or hurtful. It is important not to take such remarks too seriously, as they are often not meant to be taken literally.
The other options are incorrect because they do not accurately describe the meaning of the word "facetious." Amusing means causing laughter or amusement. Critical means expressing disapproval or condemnation. Casual means relaxed and informal.
