Final answer:
The formation of Earth's Moon is best explained by the giant impact hypothesis, where a Mars-sized body collided with the early Earth, creating debris that formed the Moon.
Step-by-step explanation:
Earth's Moon Formation
The most accepted hypothesis for the formation of Earth's Moon is option (b), a catastrophic collision of the early Earth with a planet-sized object. This is known as the giant impact hypothesis, which suggests that about 4.5 billion years ago, Earth was hit by an object roughly the size of Mars. The collision caused debris to form a ring around Earth, which eventually condensed and created the Moon. The giant impact hypothesis resolves the issues found in other theories such as the fission hypothesis, the sister hypothesis, and the capture hypothesis, which are less supported due to various problems such as compositional similarities between the Earth and the Moon, and the dynamics of celestial capture and orbits.
Earlier hypotheses for the Moon's origin such as the sister theory, which suggests the Moon formed independently alongside Earth, and the capture theory, which proposes the Moon was captured by Earth's gravity from somewhere else in the solar system, have been largely discarded. These theories struggle to explain the composition and particular orbit of the Moon, contrasting with the evidence supporting the giant impact hypothesis.