Which phenomenon occurs when the sun crosses the plane of earth’s equator

Equinox. Twice a year around March 20th and September 23rd the earth's plane cross the path of the sun causing the day hours and night hours to be almost equal to each other (12 hours of daylight, 12 hours of night). It's not exactly the same because of the sun's refraction and size, but it is fairly close.

The answer is going to be a because ik that i’m right