Final answer:
The correct answer is the Giant impact hypothesis. It suggests that the Moon was formed from the debris of a giant impact between Earth and a Mars-sized object about 4.5 billion years ago.
Step-by-step explanation:
The correct answer is A) Giant impact hypothesis.
Bill Hartman believed that the formation of the moon was caused by the Giant impact hypothesis, which suggests that the moon was formed from the debris of a giant impact between Earth and a Mars-sized object about 4.5 billion years ago. The impact resulted in the formation of a ring of debris around Earth, which then condensed and formed the Moon.