Let a,b, and c be real numbers such that a>b and c>d. Enter the letters of the statements below that must be true.

Let $a,b,$ and $c$ be real numbers such that $a > b$ and $c>d$.

Enter the letters of the statements below that must be true.

(A) $a + c > b + d$

(B) $2a + 3c > 2b + 3d$

(C) $a - c > b - d$

(D) $ac > bd$

(E) $a^2 + c^2 > b^2 + d^2$

(F) $a^3 + c^3 > b^3 + d^3$