Is the set of multiples of 4 closed under addition? Explain why or provide a counterexample if not.

AYes, because the sum of any two multiples of 4 is also a multiple of 4.

BYes, because the sum of any two multiples of 4 is also a multiple of 8.

CNo, and a counterexample is –4 + (–8) = –12.

DNo, and a counterexample is 26 + 16 = 42.