A among the five elements, the largest atomic radius is Z, so A is wrong;
B. The weaker the oxidation of simple substance, the stronger the reducibility of corresponding ions, so the simple anion of Y is weaker than that of W, so B is wrong;
The compound formed by C, Y and Z is a metal oxide, which can react with hydrochloric acid, so C is correct;
D. if z is Na, the compound NaCl aqueous solution formed by z and q is neutral, so d is wrong;
So choose C.