It was the first time such standards （ ） increased in a decade.

It was the first time such standards （ ） increased in a decade.
A、had been
B、were to be
C、have been
D、are being
【正确答案】：A
【题目解析】：过去完成时。it is the first time…和相似的结构后面的分句中，动词多用完成体。因为句子中was为过去式，所以动词用过去完成体，选A。