If X and Y Are Random Variables with E(X) =7

Short Answer

If X and Y are random variables with E(X) =7 and E(Y) = 3, then E(2X + 3Y) is: $\begin{array}{|l|l|}\hline \text { D. } & 21 . \\\hline\text { A. } & 10 . \\\hline \text { B. } & 23 . \\\hline \text { C. } & 27 . \\\hline \text { D. } & 21 . \\\hline\end{array}$