A weightless rod is acted on by upward parallel forces of `2 N` and `4N` ends `A` and `B` respectively. The total leng th of the rod `AB=3m`. To keep the rod in equilibrium a fo rce of `6 N` should act in the following manner :
A. Downward at any point between A and B
B. Downward at mid point of AB
C. Downward at a point C such that AC=1 m
D. Downward at a point D such that BD=1 m
