Final answer:
Option A: Air currents at the equator generally rise due to the Intertropical Convergence Zone (ITCZ), where the convergence of warm air causes it to ascend, leading to cloud formation and precipitation.
Step-by-step explanation:
The overall direction of global air currents at the equator is that air currents rise. This is due to the Intertropical Convergence Zone (ITCZ), a region that circles the Earth near the equator, where the trade winds of the Northern and Southern Hemispheres come together, causing air to rise due to the convergence of the winds and warming of the surface by the sun's direct rays.
The rising air typically leads to a band of cloudy and rainy weather around the equator as the warm air cools and the water vapor condenses. Additionally, the Coriolis effect, which is the deflection of moving objects (such as air) when viewed in a rotating reference frame (like the Earth), is zero at the equator, and hence has no influence on the vertical direction of the air movement at the equator. Therefore, air currents are not primarily moving horizontally to the north or south at the equator, but are instead rising upward.