Correct answer choice is :
B) Autumnal equinox
Step-by-step explanation:
An equinox is usually considered as the consequence when the plane of Earth's equator moves through the center of the Sun, which happens twice each year around 20 March and 22–23 September. When the Northern Hemisphere begins to tilt near the sun in spring, the Southern Hemisphere begins to tilt away from the sun, indicating the start of fall. Thus, in the Southern Hemisphere, the March equinox is described the autumnal equinox, and the September equinox is described the vernal equinox.