The answer is c, use of telephones (i think)
By 1973, the United States had become dependent on foreign energy sources.
28n-7=-38-3n
31n-7=38
31n=-31
n= -1
Answer: the countries belgium, canada, france, germany, greece, italy, iceland and denmark all supported the US during the cold war
Explanation: all of these countries and the US are a perfect example of a united group. (atleast, that's what i think)