Unique Rectangle Type 6
Use solution uniqueness and strong links on opposite sides of a rectangle to eliminate candidates at diagonal corners.
All candidates have been entered in the empty cells.
Assume that the puzzle has a unique solution. Candidate 2 has only two possible places in each of A and B. If candidate 2 is true at one ×, it is also true at the other ×. Therefore, the two digits can swap into another solution. That contradicts uniqueness. Candidates 2 marked × can be removed.