The velocities of two arbitrary points A and B on a rigid body are vA and vB, respectively. Which statement is correct?

A、If the rigid body is in translation, then ½vA½=½vB½ must be satisfied.;

B、If ½vA½=½vB½ is satisfied,
then the rigid body must be in translation.;

C、If the rigid body is in translation, then ½vA½=½vB½ must be satisfied and the directions of the two velocities could be different.;

D、If the rigid body is in translation, then the directions of vA and vB must be the same but probably |vA|¹|vB|.