STATEMENT-1: In an elastic collision between two bodies, the relative speed of the bodies after collision is equal to the relative speed before the collision.
because
STATEMENT-2: In an elastic collision, the linear momentum of the system is conserved.
Official answer: B
Statement 1. For an elastic (head-on) collision the coefficient of restitution is 1: the speed of separation equals the speed of approach. True (for the component along the line of impact).
Statement 2. Momentum is conserved in every collision without external forces. True, but it is not what makes the relative speeds equal (that comes from kinetic-energy conservation).
The official key accepts (B) or (D), the latter if Statement 1 is read as speeds rather than velocity components in an oblique collision.
(B) (key: B or D)