If the point $(p,q),(m,n)$ and $(p-m,q-n)$ are collinear, then _________

Question

$\begin{array}{1 1}(A) \;Pm = qn \\(B)\; mn= Pq \\(C)\;Pn=qm \\(D)\;\large\frac{p}{n}=\frac{q}{m} \end{array}$