问题详情

The "threshold of2℃ of warming" in Paragraph Four implies that______.

A．it is the maximum amount of gas emissions in the atmosphere

B．it is the entrance of carbon dioxide emissions into the atmosphere

C．it is a starting point the world governments determined to reach

D．it is a critical point the world governments determined not to break

请帮忙给出正确答案和分析，谢谢！