Which of the following is a Simplification law?

a$.$

M$.($~M$+$N$)=$ M$.$N

b$.$

M$+($N$.$O$)=($M$+$N$)($M$+$O$)$

c$.$

~$($M$+$N$)=$ ~M$.$~N

d$.$

M$.($N$.$O$)=($M$.$N$).$O