A lump of sticky chewing-gum with mass m moves at speed v toward another lump of mass M at rest. They collide and stick together, both moving at speed V. Nothing else is known about the conditions under which the collision takes place. Which of the following statements is the most correct?
(a) Neither total kinetic energy nor total linear momentum can be conserved.
(b) This is an elastic collision in which both total kinetic energy and total linear momentum are conserved; the final speed is V = v/2.
(c) This is an inelastic collision, and in such collisions, total linear momentum is always conserved; the final speed is V = v/4.
(d) This is an inelastic collision in which total linear momentum is conserved, provided no external force can deliver an impulse to the system during the collision.