The answer is B) Decrease the risk of Nuclear War
The 1970s saw the cold war at its height with a nuclear threat looming. There was hysteria among the general population and the troubles of the Cuban Crisis were fresh in people's minds.
As the Soviet Union kept on testing bigger, larger and more dangerous nuclear weapons, many in the United States wanted to improve relations with the Soviets to at least a point where the Nuclear threat for both countries can be diminished greatly.
Hence, the South Carolinians were in favor of improving relations with the Soviets