Which answer option below describes the best way to increase the accuracy of a confidence interval calculation?

The answer is c but this has to be twenty characters long

The truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey