The correct answer is C. 1.0.
The coefficient of restitution (COR) is a measure of how much energy is lost when two objects collide. It is defined as the ratio of the relative velocity of separation to the relative velocity of approach of the two objects just before and after the collision.
For perfectly elastic bodies, the COR is 1. This means that no energy is lost during the collision, and the two objects rebound off of each other with the same speed that they had before the collision.
For perfectly inelastic bodies, the COR is 0. This means that all of the energy is lost during the collision, and the two objects stick together after the collision.
For real-world objects, the COR is always between 0 and 1. The closer the COR is to 1, the more elastic the collision is.
Option A is incorrect because the COR cannot be zero for perfectly elastic bodies.
Option B is incorrect because the COR is not always 0.5. It can be any value between 0 and 1.
Option D is incorrect because the COR is not always between 0 and 0.5. It can be any value between 0 and 1.