Block A has mass 1.00 kg and block B has mass 3.00 kg. The blocks collide and stick together on a level, frictionless surface.After the collision, the kinetic energy (KE) of block A is
选项：

A:1/9 the KE of block B
B:1/3 the KE of block B
C:3 times the KE of block B
D:9 times the KE of block B
E:the same as the KE of block B