我觉得应该选B，
虚拟语气是 shoul + do 或是 did
如果用did的话那主句时态是过去时从句应该相应退一格，所以是过去完成时

毫无疑问，A。

直接翻译 她说是他们吃晚饭的时候了 可以看出 A吧

It is (high) time that sb. did sth.

A
Unreal past tenses after "wish", "would rather/sooner" and "it is time" do not change:
"We wish we didn't have to take exams,' said the children.
=> The children said that they wished they didn't have to take exams.
"Bill wants to go alone," said Ann, "but I'd rather he went with a group."
=> Ann said that Bill wanted to go alone but that she 'd rather he went with a group.
"It's time we began planning our holidays," he said.
He said that it was time they began planning their holidays.