If $A$ and $B$ are square matrices of same order, then which of the following statements is/are always true ? (i) $(A + B) (A - B) = A^2 - B^2$ (ii) $AB = BA$ (iii) $(A + B)^2 = A^2 + AB + BA + B^2$ (iv) $AB = 0 \Rightarrow A = 0$ or $B = 0$ (A) Only (i) and (iii) (B) Only (ii) and (iii) (C) Only (iii) (D) Only (iii) and (iv)