18−(3+3)=
Let's simplify this expression while following the order of operations which states that exponents come before multiplication and division, which come before addition and subtraction, and that parentheses come before all of them,
therefore we'll start by simplifying the expression inside the parentheses and perform the addition within them, then we'll perform the subtraction operation that applies to the expression in parentheses:
Therefore the correct answer is answer D.
12