Which of these is a valid conclusion?

Question

Answer
A. All sergeants clear a fitness test.
Harry has cleared a fitness test.
Therefore, Harry is a sergeant.
B. All sergeants clear a fitness test.
Harry has not cleared a fitness test.
Therefore, Harry is not a sergeant.
C. All sergeants clear a fitness test.
Harry is a sergeant.
Therefore, Harry has not cleared a fitness test.
D. All sergeants clear a fitness test.
Harry is not a sergeant.
Therefore, Harry has not cleared a fitness test.