Options
(a)must/must
(b)need not/need not
(c)must/need not
(d)need not/must
Answer:
C, must/need not
Because Blaine Blogger reviews movies on his blog, movie theaters allow him in for free. Nellie Newspaper Reporter also gets free admission to movies. Blaine must disclose on his blog that he receives free tickets. Nellie need not disclose in her articles that she receives free tickets.
The modals must and need not have the same form regardless the subject. There is no ending with he/she/it.
If you want to say the something. is unnecessary, use need not, not must not. (The negation of must means not allowed to.)
Needn't is very different from mustn't. It is used to say that you do not have to do something, it is not necessary to do something.