A body of mass M is acted upon by a force F and acceleration produced is 'a' . If three equal forces each equal to F and inclined to each other at $120 ^{\circ}$ act on the same body , the acceleration produced will be

Question

$$(a)\;zero \quad (b)\;\frac{a}{\sqrt 3} \quad (c)\;\sqrt 2 a \quad (d)\;3a$$