选择题 英语,为什么不选D,而选C?

题目

选择题 英语,为什么不选D,而选C?
However, the world’s best driver at least needs one second to react. （12 ）, when he takes action, he needs one more second.
12. A So B However C Besides D Therefore

答案

因为后一句话是前一句话的补充,而非结果.