help me


A = {a,b,c,d,e,f,1,2}
B = {b,c,d,f}
C = {e,1,2,3}

clusters are given

According to clusters, which one is wrong?

A) A ∪ B = A
B) A ∩ B = B
C) B ∩ C = Ø
D) s(A ∩ B) = 3
E) s(B ∪ C) = 7

help me​​