The Correct Answer
Part A: one
Part B: zero
The moon is
tidally locked to the earth, and the former's orbit around the latter is not too elongated. The result is synchronous rotation, in which the period of the moon's orbit around the earth is the same length as the period of its rotation around its axis. Both are about twenty-eight (28) days. Under this condition, the sun rises once on the moon in any twenty-eight day period, and the same side of the moon always faces the earth. From the perspective of the moon, the earth stays in the same place in the sky, all the time. No "earth rise", no "earth set" on the moon, when viewed from most of the surface of the moon that we can see from the earth. (OK, so
libration causes a little movement of the earth in the sky, relative to the horizon, when viewed from the moon.)
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