Why do we always see the same side of the moon from Earth?

The reason we always see the same side of the Moon from Earth is because the Moon rotates on its axis and revolves around the Earth in synchronous rotation. This means that the time it takes for the Moon to complete one rotation—one spin on its axis—is the same as the time it takes for the Moon to orbit the Earth. This synchronization results in the Moon showing the same face toward Earth at all times.

As the Moon travels around Earth, its rotational period matches its orbital period, leading to a situation where we are constantly facing the same side. This phenomenon is often referred to as "tidal locking."

The other provided options do not accurately explain this phenomenon. While the Moon does get lit by the sun and has phases, this does not relate to the visibility of its surface from Earth. Option B incorrectly suggests a different rotational speed, and option D implies that the face we see is away from the sun, which is also misleading since we can see a lit portion of the Moon depending on its phases. The correct understanding of the Moon's synchronous rotation is essential in grasping why we observe only one hemisphere from our vantage point on Earth.