单项选择题
The following sentences tell what happened many years ago. Which is the right order of the events（）
A．Archimedes took a bath
B．Archimedes discovered his principle
C．The king of Syracuse asked him to sovle a problem
D．Archimedes did the experiment on his crown
A. c; a; b; d
B. h; c; a; d
C. b; c; d; a
D. c; a; d; b