物体做平抛运动，正确的说法是[ ]

A．由于物体只受重力，所以物体在下落过程中只受重力的冲量

B．尽管物体只受重力，物体在曲线下落过程中动量变化量的方向也不会竖直向下

C．轻物体和重物体在自由下落中，只要经过的时间相同，重力的冲量也相同

D．物体在下落过程中，相等时间内的平均速度不相同，所以相等时间内重力的冲量也不相同

Which of the following statements concerning taxable bonds is TRUE（）

A. Corporates have the lowest yields, followed by Treasuries, then by corporates, which provide the highest returns.

B. Treasuries have the lowest yields, followed by corporates, then by agencies, which provide the highest returns.

C. Treasuries have the lowest yields, followed by agencies, then by corporates, which provide the highest returns.