The solar equator, the region of Earth where the sun is directly overhead, moves from 23.5°N to 23.5°S latitudes and back over the course of a year. Why?

A. Earth wobbles on its axis during the year;

B. The position of the poles changes by this amount annually;

C. Earth’s axis is 23.5° from perpendicular to the rays of the sun;

D. Earth moves 23.5° toward the sun in summer and 23.5° away from the sun in winter;

E. Ocean currents carry heat from the tropical ocean north in summer and south in winter