Nothing wrong with this question, but setters do need to be careful when asking about the last man to walk on the Moon.
The same question was asked, from a different angle, in Stockport Quiz League (knockout competition) on 24 January. The question was simple enough: "Who was the last man to walk on the Moon?" The answer given was "Harrison Schmitt", but "Eugene Cernan" would actually have been a more correct answer.
The cause of the confusion is that Harrison Schmitt became the twelfth and last Apollo astronaut to step onto the Moon, when he followed Eugene Cernan on their first excursion outside the Apollo 17 lunar module on 11 December 1972. But at the end of Cernan and Schmitt's third lunar excursion, on 14 December 1972 (approximately 00:40 EST, 05:40 GMT), Schmitt was the first to step back into the lunar module, leaving Cernan as the last man to walk on the Moon (to date).
It's not easy to phrase a question to which the answer is unambiguously Schmitt, without mentioning Cernan and without tying yourself in knots. The best I can come up with is something like "Of the twelve Apollo astronauts that walked on the Moon, who was the twelfth and last to step onto the lunar surface?"
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