What should the pre-condition P be in each of the following correctness statements for the statement to be an instance of Hoare's axiom scheme? All variables are of type int. (a) P { x = 1; } x y + 100 (e) P { x = x*y*z + 1; } y*y > z + 100 (f) P { x = x + y; } Exists(y=0 ; y z+8 (h) P { x = x + y; } Exists(y=0 ; y x+11