According to an observer on the Moon, which of these bodies could occasionally appear as crescent shaped?

Question

Quizplus · Accepted Answer

From the perspective of an observer on the Moon, the Earth can appear as crescent shaped. This is because the Earth and Moon are in a system where they reflect sunlight onto each other, and the phase of the Earth as seen from the Moon is opposite to the phase of the Moon as seen from Earth. When the Moon is nearly between the Earth and the Sun (a new moon phase from Earth's perspective), an observer on the Moon would see the Earth as mostly illuminated, potentially with a crescent shape when the alignment is not directly in line with the Sun.

According to an Observer on the Moon, Which of These