Hi there! You are subtracting a negative number, which is basically the same thing as adding, because two negatives make a positive. B and C is out, because they do not fit the expression. You are actually adding both numbers and anytime you have to subtract a negative number, you add. When you do basic math, 4 + 7 is 11. Both numbers are negative and D does not work, because you're adding from a negative number. The only answer choice that has the expression is A. The answer is A.