The correct answer to the question is : B) More force.
EXPLANATION:
Before going to answer this question, first we have to understand Newton's second law.
As per Newton's second law, the total external force acting on a body is equal to the product of mass with acceleration of the that body.
Mathematically force F = ma
Here, m is the mass of the body, and a is the acceleration.
From above, we see that force is directly proportional to mass.
As per the question, we have helicopter and bullet. Bullet has less mass as compared to helicopter.
Hence, more force is required to bring the helicopter to the same speed as the bullet.
