[单选题]
A stone is thrown straight up. At the top of its path, the h u p4k;p)raih+kpw6b tck+a+d)40 tgnet fg9j6)t-c t.sf /kzimlorce acting on it.)mc9lf-i6kztt sj g / is
A. greater than its weight.
B. greater than zero, but less than its weight.
C. instantaneously equal to zero.
D. equal to its weight.
