The three hypotheses do not agree about the approximate duration of the LHB. Hypothesis 1 is silent on the topic of duration, Hypothesis 2 claims that the LHB would have lasted billions of years, and according to Hypothesis 3, the duration was relatively brief.

Hypothesis 1 says that the origin of the debris was an asteroid or comet orbiting the Sun, Hypothesis 3 says that the debris came from a body specifically within the Earth-Moon system, and Hypothesis 2 denies that there was some sort of cataclysmic event that triggered the debris, instead citing a period of billions of years of continuing heavy bombardment throughout the inner solar system.

All three hypotheses agree that the LHB eventually ended. The LHB is what caused the major craters, so since all of the hypotheses discussed by the author agree that the LHB ended, they would agree that cratering decreased significantly after the LHB.

We know that life could not have survived until after the LHB. The passage is silent on what happened with regards to life before the LHB. Thus, the passage does not suggest that the author believes that all three hypotheses agree with (D), because we just don’t know what the hypotheses say about this claim.

We can’t say that the author implies that all three hypotheses agree with this claim. The hypotheses don’t specifically talk about the amount of debris involved. We do know that Hypothesis 3 says that the debris from the LHB would have been swept up quickly, and Hypothesis 2 says that the LHB would have lasted billions of years, so at least these two hypotheses likely disagree on the amount of debris involved.