:Given the jointly PDF function as: $fx,y(x,y)=0\mathrm{.}05[u(x)-u(x-5)][u(y)-u(y-4)],$ the value of the $E[x]$ is

$2.$A

$2\mathrm{.}5.$B

$1\mathrm{.}5.C$

$3.3$