Which option best explains why this statement describes a civic duty and not a civic responsibility? Every male U. S. citizen over the age of 18 must sign up with the Selective Service. If a war breaks out, these men could be required to serve in the military. O A. Citizens do not have a choice about signing up. B. The rule deals with issues of war and national safety. C. Only citizens over the age of 18 are required to sign up. O D. The rule does not apply equally to male and female citizens.