Imagine you hear a radio ad that says a candidate for mayor of your city bribed local organizations to gain their votes. which of the following is true?

select one:
a. if the accusation is true, the first amendment protects the maker of the radio advertisement.
b. if the accusation is false, the first amendment protects the maker of the radio advertisement.
c. the candidate can sue the maker of the ad because the first amendment protects nothing said on radio.
d. the candidate can sue the maker of the ad because the first amendment protects everything people say.

i believe the answer's b, can someone check it for me?