A binary operation $\oplus$ on a set of integers is defined as $x\oplus y=x^2+y^2$ . Which one of the following statements is TRUE about $\oplus$?

•  (A) Commutative but not associative
•  (B) Both commutative and associative
•  (C) Associative but not commutative
•  (D) Neither commutative nor associative