A
$M \cup C_{M \cup N} N=M \cup N$
B
$C_{M \cup N}(M \cap N)=\left(\complement_{M \cup N} M\right) \cup\left(\complement_{M \cup N} N\right)$
C
$M \cap C_{M \cup N} N=M \cap N$
D
$C_{M \cup N}(M \cap N)=\left(\complement_{M \cup N} M\right) \cap\left(C_{M \cup N} N\right)$
E
F