9-11 Let n>1 be a fixed natural number. Which of the followtng iw an inner produet on the vector pace ot xn real Nymmetrie matrices? (a) (4, B)= (trace(A))(trace(B) (b) (4, B)= trace(AB) (c) (A, B)- determinant (AB) (d)(4, B) trace(4) + trace(B) CSIT