The correct answer is D. inferior.
The phrase “a fish out of water” is an idiom that means “to feel uncomfortable or out of place in a particular situation.” In this case, the speaker is feeling inferior to the business tycoons because they are not as successful or experienced in business.
The other options are incorrect because they do not accurately describe the speaker’s feelings. Option A, troubled, is incorrect because the speaker is not necessarily feeling troubled, but rather uncomfortable or out of place. Option B, stupid, is incorrect because the speaker does not necessarily feel stupid, but rather inferior. Option C, uncomfortable, is the closest of the incorrect options, but it does not fully capture the speaker’s feelings. The speaker is not simply uncomfortable, but rather feels inferior to the business tycoons.