Is A or B plural or singular?
psichologyanswers.com › library › lectureEven 'the A and the B' could take singular form, too. All versions (no article, one article, two articles) can be singular or plural. It depends on whether the writer regards A and B as a combined phenomenon or as separate phenomena. IS IT A and B's or A's and B's? The more conservative use is "A's and B's". The apostrophe does not show possession in this case.