Based on Question $1, Let X, and Y be two independent random variables such that E(X)=2, Var(X)=4, E(Y)=7, and Var(Y)=1. Find: var(3X+7) A. 13 B. 9 C. 28 D. 36 OC OB OD OABased on Question 8, The conditional function of Y given X. A. fly/x)=(12y+6)/5 B. fly/x)=fly)=(2x+y)/(4x+2) C. fly/x)=(6y+12)/5x D. fly/x)=(2x+y)/(4+2x) OA OD OC OBBased on Question 8, The (marginal) density function of X. A. f(x)=0.25(4x+2) B. f(x)=2/5+3x/5 C. f(x) (6x+12)/5 D. B. f(x)=2x/5+3/5 OC OA OD O BBased on Question 8, The (marginal) density function of Y. A. f(y)=8(2y+1) B. f(y)=2/5+3y/5 C. fly)=0.5(1+y) D. f(y)=0.25(1+y) OA OB OC ODLet X and Y be random variables having joint density function f(x, y) = c(2x + y), 0