[单选题]
Ball A is dropped fro4e ra/f48gsev m the top of a building. One pvbss6q)u zns:+( l( dsecond later, ball B is dropped from the same b(s(b u qv6s+z dnpsl):uilding. As time progresses, the distance between them
A. increases.
B. remains constant.
C. decreases.
D. cannot be determined from the information given.
