Consider the following factors: 1) Rotation of the Earth 2) Air pressure and wind 3) Density of ocean water 4) Revolution of the Earth Which of the above factors influence the ocean currents?

Ocean currents are driven by wind, by density differences in seawater, and modified by the Earth's rotation. So the answer is B (1, 2 and 3).

Statement 1 (rotation): The Coriolis effect deflects currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, which is why gyres like the North Atlantic gyre circulate clockwise.

Statement 2 (air pressure and wind): Persistent winds such as the trade winds and westerlies drag the surface water and produce the major surface currents.

Statement 3 (density): Cold, saline, dense water sinks and warmer, less dense water rises. This thermohaline circulation drives the deep ocean conveyor belt.

Statement 4 (revolution): The Earth's revolution around the Sun causes seasons and changes insolation, but it does not directly set ocean water in motion. This is the factor that does not belong.

Core concept: the forcing of ocean circulation, with wind-driven surface currents and density-driven deep currents shaped by the Coriolis effect. Mains angle: ocean currents move heat poleward and moderate regional climate, which links to GS-1 geography (climatology) and to monsoon and climate change questions in GS-3.

Trap: Aspirants associate "Earth's motion" with seasons and pick statement 4, or drop statement 3 because they think only wind matters.