It is the third time that he told us about his story.
It was the third time that he had told us about his story.
这是固定句型。it is the first/ second/ third time that sb. did sth. 这是某人第几次做这件事情了。
如果be动词是一般现在时,从句中的谓语动词用过去时。
如果be动词是过去时的话就用过去完成时。
所以选B
是个固定句型,好长不看了,不知道对否,前面过去式的话从句就要用过去完成时;前面是一般现在时态从句用现在完成时态仅供参考,这是个固定句型阁下可以记住
选B
类似例句有:
It was the third time that he had been out of work that year.
这是他那一年第三次失业了。