Mark the letter A B C or D to indicate the correct response to each of the following exchanges, Mark the letter A; B; C or D to indicate the correct response to each of the following exchanges. , Mark the letter A; B; C; or D to indicate the correct response to each of the following exchanges, Mark the letter A B C or D to indicate the correct response to each of the following exchanges, Mark the letter A; B; C or D to indicate the correct response to each of the following exchanges