Which of the following is a requirement for all retail firearm purchases in South Carolina?

A background check is required for all retail firearm purchases in South Carolina. This is to ensure that the buyer is eligible to purchase a firearm and does not have a criminal record or other disqualifying factors. Option A is incorrect because a hunting license is not required for all retail firearm purchases, only for certain types of firearms such as hunting rifles. Option B is incorrect because South Carolina does not have a firearm registration requirement. Option D is incorrect because there is no residency requirement for purchasing a firearm in South Carolina.