When did stockpiles of strategic nuclear weapons begin to decline in the United States?
a. the end of the 1960s
b. the late 1970s
c. the end of the 1990s
d. the mid-1990s
Stockpiles of strategic nuclear weapons began to decline in the United States in "d. the mid-1990s," due to the fact that this was when the Cold War really began to come to a close.