Agriculture was a step in human progress ________ which subseque

Agriculture was a step in human progress ________ which subsequently there was not anything comparable until our own machine age.
A、in
B、for
C、to
D、from
【正确答案】：A
【题目解析】：in which = where 农业是人类史上的一步在这一点上是没有什么能匹敌的。