The question and all of the choices are rather messy and misleading.
Here's a simple statement that you can use to make the best match:
If the two forces are equal, then more work is done by the force that
continues to be applied through the greater distance.
The momentum of each vehicle is (its mass) times (its speed).
Voltage =Current * Resistance
= 9 * 43
Voltage = 387 V
Answer:

Explanation:
Force on a current carrying rod due to magnetic field is given as

here we know that
current in the rod


now magnetic force is balanced by the weight of the rod
so we will have



When it travels 3m ,4m and 5m it means 12m is right answer.