Question

at what latitude are none of the stars on the celestial sphere circumpolar?
0 degrees latitude, the equator
90 degrees s latitude, the south pole
90 degrees n latitude, the north pole
45 degrees n latitude

Explanation:

At the equator (0 degrees latitude), the celestial poles are on the horizon. As a result, no stars are circumpolar. Circumpolar stars are those that never set or rise and are always above the horizon. At the poles, many stars are circumpolar, and at 45 - degree latitude, some stars are circumpolar.

Answer:

A. 0 degrees Latitude, The Equator