A sports team of 11 students is to be constituted,choosing at least 5 from class XI and 6 from XII.If there are 20 students in each of these classes,in how many ways can the team be constituted?

Question

$\begin{array}{1 1}(A)\;2[20C_5.20C_5]\\(B)\;[20C_5.20C_5]\\(C)\;20C_5\\(D)\;20C_6\end{array} $