Answer: B
Step-by-step explanation:
In collision, whether elastic or inelastic collisions, momentum is always conserved. That is, the momentum before collision will be equal to the momentum after collision. 
Since momentum is a vector quantity, the direction will also be considered. 
Momentum = MV - mU
Let
 M = 1100 kg is going north 
at V = 18 m/s and the other car
 m= 1300 kg is going south 
at U = 16m/s.
Substitute all the parameters into the formula 
Momentum = (1100 × 18) - (1300 × 16)
= 19800 - 20800
= - 1000
It's due south since the final answer is negative. 
= 1000 kgm/s due south.
Therefore, the momentum of the system of the two cars after the
collision is 1000 kgm/s due south