[单选题]
The driver of a motorboat that can move at 1 lv-kjzh 2r-fdt(jv 562dq in30 m/s inr/4fov9e+ pdx still water wishes to travel directly across a narrow strait in which thefvxd9r + /e4po current flows at 5.0 m/s. At what angle upstream should the driver head the boat?
A. $27^{\circ}$
B. $30^{\circ}$
C. $60^{\circ}$
D. $63^{\circ}$
