挂钟分针的长10cm,经过45分钟,它的针尖转过的路程是( )
A:15π2cm
B:15πcm
C:75π2cm
D:75πcm
① ____ A. mine B. my C. your
② ____ A. hers B. you C. yours
③ ____ A. their B. ours C. our