UPSC CSE Prelims

Correct Option: B Explanation: Westward-flowing North and South Equatorial Currents pile up water in the western ocean basin; the resulting sea-level/pressure gradient drives an eastward Equatorial Counter Current. Option-wise Analysis: A: Incorrect - The Coriolis effect influences ocean circulation but does not by itself explain this eastward return current. B: Correct - Convergence and accumulation of water carried by the two westward equatorial currents generate the eastward return flow. C: Incorrect - Salinity differences are not the primary mechanism. D: Incorrect - Equatorial calms alone cannot explain the directional current.