[单选题]
If you walk 6.0 km in3vke/g n0 ,yt6 .apjku a st+p:j9n jie2tm raight line in a direction north of east and you end up 2.0 km north and severi j t2p:emn+j9al kilometers east. How many degrees north of east have you walked?
A. $19^{\circ}$
B. $45^{\circ}$
C. $60^{\circ}$
D. $71^{\circ}$
