What is a planet’s period of rotation?
A.
the shape of its orbit
B.
its tilt relative to the sun
C.
one complete spin on its axis
D.
one complete orbit around the sun

"C. one complete spin on its axis" is the correct answer. One complete orbit around the sun by a planet would be referred to as a period of rotation. Periods describe one full movement.

The Planet's period of rotation Is one complete spin on its axis.