[单选题]
A ball of mass 0.10 kg is dropped from a height cf ; a.-fikgfeh9izt6c owi-hw ;9.+dof 12 ,7(th1z a0unjp hg8wg1o1hk- e*ab nmm. Its momentum when it strikes the grouz(jbtn7w 1po-8 h h,hk0ga*umna1e 1gnd is
A. 1.5 kgm/s.
B. 1.8 kgm/s.
C. 2.4 kgm/s.
D. 4.8 kgm/s.
