Two objects of mass `` 10\, kg `` and `` 20 \, kg `` respectively are connected to the two ends of a rigid rod of length `` 10\, m `` with negligible mass. The distance of the center of mass of the system from the `` 10\, kg `` mass is :
(A) `` 5 \, m ``
(B) `` \frac{10}{3} m ``

(C) `` \frac{20}{3} m ``
(D) `` 10\, m ``