Which one is correct?

A) That is why not only DO they get electronic games for themselves but also for their friends and family.

B) That is why not only they get electronic games for themselves but also for their friends and family.

I know there are negative adverbs and some expressions that make the sentence follow a question word order when they are placed at the beginning, but I am not so sure about this case since it is introduced by THAT IS WHY.