If $A=\{3,5,7,9,11\},B=\{7,9,11,13\},C=\{11,13,15\}$ and $D=\{15,17\}$.Find $A\cap D$

Question

$\begin{array}{1 1}(A)\;\phi&(B)\;\{3,5,7,9,11\}\\(C)\;\{15,17\}&(D)\;\{3,5,7,9,11,15\}\end{array} $