If A={3,6,9,12,15,18,21},B={4,8,12,16,20},C={2,4,6,8,10,12,14,16},D={5,10,15,20} (x) D-B

Question

$\begin{array}{1 1}(A)\;\{5,10,15\}&(B)\;\{5,10,15,20\}\\(C)\;\phi&(D)\;\{4,8,14,16,20\}\end{array}$