Which of the following is (are) correct regarding the sharing of the salvage award？ ______. ① The proportionate division of the award depends in great measure on the circumstances． ② The award to the crew is usually divided according to the rank of the crew． ③ The master and senior officers usually receive a larger percentage than the seamen，unless one or more of the seamen renders extraordinary service．

A. ① and ③ only
B. ② and ③ only
C. ① and ② only
D. ① ②，and ③