Their university is located on a beautiful lake, _____ of this developing city. [ ]

A. southeast thirty miles

B. thirty miles southeast

C. thirty miles to southeast

D. to thirty miles southeast

课外活动中，小明和同学们一起，利用太阳能驱动玩具车并记录相关数据，实验后，根据实验数据绘制图象如图所示，由此可知：甲车全程的平均速度是____m/s；前20s内，乙车比甲车多运动了____m。