The Supreme Court's Ruling in District of Columbia V

The Supreme Court's ruling in District of Columbia v. Heller meant that

A) the Second Amendment referred only to the arming of National Guard troops.
B) the Second Amendment is unlimited.
C) the government cannot prohibit the carrying of firearms in schools and government buildings.
D) the District of Columbia could not prohibit the keeping of handguns in the home.
E) states were free to ban the keeping of handguns in the home.