7. Incorrect. The answer is false
not true. A' = T - A or all
the elements not bordered by blue, B' = T - B, or all elements not highlighted
with yellow. The difference between A' and B' = (T-A) - (T - B) = B-A gives the
elements of B which do not belong to A. So, we have that A' - B' = {Fe, Co, Ni,
Zn}. The set does not include Cu.