单选题 According to the passage, scientists have concluded which of the following from the discovery of the large amount of deuterium found in comets?

• (A) Comets do not contain enough deuterium to have solely created the Earth's oceans.
• (B) Given the ratio of deuterium to ordinary hydrogen in seawater, comets cannot have contributed to the Earth's oceans.
• (C) It is likely that comets contain less Xenon than meteorites do.
• (D) Given the low level of deuterium in the waters of Earth's oceans, comets cannot be its sole source.
• (E) Comets now play a greater role in the creation of the Earth's oceans than was previously thought.