Answer
Africa was not a continent that John A. Calhoun served as an ambassador in. Calhoun was an American politician who served as the seventh vice president of the United States from 1825 to 1832. He also served as the 12th secretary of state from 1844 to 1845. Calhoun's diplomatic experience was limited to his service as minister to the United Kingdom from 1844 to 1845.