On the power set p of a non-empty set A, we define an operation Δ by XΔY=(X∩Y)∪(X∩Y)Then which are of the following statements is true about Δ (a) commutative and associative without an identity (b) commutative but not associative with an identity (c) associative but not commutative without an identity (d) associative and commutative with an identity