Which of the following is true? a. europeans and americans had made little impact on korea by 1860. b. the japanese emperor signed the treaty of amity and commerce with the u. s. c. president millard fillmore sent commodore perry to open korea to american ships. d. commodore perry’s visit to japan frightened the qing emperor into signing the treaty of nanjing. i am guessing it is b but not so sure. can you me?