[单选题]
Ball A is dropped from the top o95ku9vz, h bz f3iy(xr5hae b7fx sk lkf11y85e a building. One second later, ball B is dropped from the same building. As time progresses, the difference in their ss1l5kx1 f8ekypeeds
A. increases.
B. remains constant.
C. decreases.
D. cannot be determined from the information given.
