When two bodies stick together after a collision, the collision is said to be:

When two bodies stick together after a collision and move as a single combined mass, the collision is inelastic — more precisely, a perfectly (or completely) inelastic collision.

In any collision, linear momentum is conserved. In an elastic collision the total kinetic energy is also conserved and the bodies separate after impact. In an inelastic collision some kinetic energy is converted into other forms (heat, sound, permanent deformation), so the bodies do not bounce back perfectly.

The case where the bodies coalesce and move together with a single common velocity is the limiting (perfectly inelastic) case, in which the loss of kinetic energy is the maximum allowed by momentum conservation. For two masses m1 and m2 with initial velocities u1 and u2, the common final velocity is v = (m1·u1 + m2·u2) / (m1 + m2).

Since the bodies stick together, the collision is inelastic. Hence the correct answer is 'Inelastic'.