The values of $m$ for which the system of equations $3 x+m y=m$ and $2 x-5 y=20$ has a solution satisfying the condition $x>0, y>0$, are
(A) $m \in\left(-\infty, \frac{-15}{2}\right) \cup(0, \infty)$
(B) $m \in\left(-\infty, \frac{-15}{2}\right) \cup(30, \infty)$
(C) $m \in\left(-\infty, \frac{-15}{2}\right) \cup(0,30)$
(D) None of these