A thin conducting ring of radius R is given a charge +Q. The electric field at the centre O of the ring due to the charge on the part AKB of the ring is E. The electric field at the centre due to the charge on the part ACDB of the ring is :

Question

$\begin {array} {1 1} (1)\;3\: E\: along\: OK & \quad (2)\;3\: E\: along\: KO \\ (3)\;E\: along\: OK & \quad (4)\;E\: along\: KO \end {array}$