The Moon does not rotate on its axis. The Moon is not visible during the day. The Moon has phases that coincide with its rate of rotation. The Moon rotates at the same rate that it revolves around Earth.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Why has only one-half of the Moon ever been observed from Earth?
Possibilities:
- The Moon does not rotate on its axis.
- The Moon is not visible during the day.
- The Moon has phases that coincide with its rate of rotation.
- The Moon rotates at the same rate that it revolves around Earth.

The Moon rotates at the same rate that it revolves around Earth.