Let a@b represent the operation on two numbers, a and b, which selects the larger of the two numbers, with a@a=a. Let a!b represent the operator which selects the smaller of the two numbers, with a!a=a. Which of the following three rules is (are) correct?
(1)a@b=b@a(2)a@(b@c)=(a@b)@c(3)a!(b@c)=(a!b)@(a!c)
(A)(1) only(B)(2) only(C)(1) and (2) only(D)(1) and (3) only(E)all three