The correct option is D All the above are correct.
Rigid body is a solid body in which deformation is zero or very small such that it can be neglected. So, the shape and size will always be the same.
Therefore, the distance between any two given points in a rigid body remains constant with time, regardless of external forces exerted on it.
Also, velocity of each particle relative to any other will always be zero.
Hence all the options are correct for rigid body.