Which of the following situations exhibits a reasonable limit placed on the first amendment in the interest of the common good?

This is multiple choice I found the answers: 
a. Television shows are canceled when criminals claim they learned how to commit crimes by watching.
 b. Groups of three or more people must obtain a license from the city before meeting in any local parks.
 c. News reporters traveling with troops overseas must not reveal their location or the soldier's identities.
 d. A confessed criminal is forced to speak in court and describe his or her crimes in detail for public record.
Answer is C