Consider two bodies which are accelerating towards each other, collide after some time. Which one of the following statements is correct about the system?

a) The total momentum remains conserved about the instant of collision
b) The total momentum remains conserved during collision
c) The total momentum does not remain conserved
d) The total momentum remains conserved

Only a

As the bodies are accelerating, there is net externally applied force and thus, the momentum is NOT conserved.

Just at the instant of collision, both the bodies have a constant velocity. Hence, just before and just after the collision, the total momentum will remain conserved.