[单选题]
A ball of mass 0.10 kg is dropped from a heighmfpd r7vcd(j8k-;6dvt of 12 m.w qv(r vfbp+ m)9-o(iiyte)3 ojs )8y3tap:pf Its momentum when it strikes thi9yr3j (8 t)-ti( +)3pw:vmyq s )pfaoopvfbee ground is
A. 1.5 kgm/s.
B. 1.8 kgm/s.
C. 2.4 kgm/s.
D. 4.8 kgm/s.
