[单选题]
Suppose a ball is thrown straight up. Wh:6q(mr-vl b3w c7rim pat is itsnlmmwc+b,v y3/j81js cef7j 5 acceleration just before it reache8vc7mb5,1ey3 cjn/ m f jswl+js its highest point?
A. zero
B. slightly less than g
C. exactly g
D. slightly greater than g
