Which of the following statements are correct ?

(A) $var (aX+b)= a^2 var (X)$

(B) $var(X)=E(X^2)-\begin{Bmatrix} E(X)\end{Bmatrix}^2 $

(C) $E(aX+b)=aE(X)+b$

(D) $E(X)=\sum\limits^{n}_{i=1}p_ix^2_i $

Choose the correct answer from the options given below :

(A), (B), (C) Only