❓ 题目 According to the passage, what is the main argument for choosing the mid-20th century as the start of the Anthropocene?
- A. A) It coincides with the first human use of tools and agriculture.
- B. B) It provides a globally synchronous and measurable marker, such as plutonium fallout.
- C. C) It marks the beginning of stable climatic conditions after the last ice age.
- D. D) It is the period when human population first exceeded one billion.