The answer is C. The program prints:
[46, 40, 34, 12, 5, 2]

Why?
sort() puts the list in order, smallest first. reverse=True flips it, so the biggest comes first. It changes the list itself.
The code again
scores = [12, 34, 46, 2, 5, 40]
scores.sort(reverse=True)
print(scores)
Try it: change one number in the program and predict the new output before you run it.