The correct answer is choice (c).
* is not commutative. Take this counterexample.
$2 * 4 = 4$, and $4 * 2 = 1$.
Clearly $2 * 4$ is not equal to $4 * 2$.
* is not associative. Let's see if $2 * (3 * 4)$ is equal to $(2 * 3) * 4$.
LHS: $2 * (3 * 4)$ = $2 * 2$ = 2.
RHS: $(2 * 3) * 4$ = $1 * 4$ = 4.
Clearly both are not equal, hence * is not associative either.
However * does have an identity element, and we can clearly see that the identity element is 1.