The economic concept of guns or butter means that
a. a person can spend money on either sports equipment or food.
b. a company must decide whether to manufacture guns or butter.
c. a government must decide to produce more or less military or consumer goods.
d. a government can buy unlimited military and civilian goods if it is rich enough.
The economic concept of guns or butter means that "c. a government must decide to produce more or less military or consumer goods," since there aren't enough funds or resources to produce lots of both.