Electric charges of `1muC, - 1muC and 2muC` are placed in air at the corners A, B and C respectively of an equilateral triangle ABC having length of each side 10 cm. The resultant force on the charge at C is
Options:
(a) `0.9 N`
(b) `1.8 N`
(c) `2.7 N`
(d) `3.6 N`