Final answer:
Newton's third law of motion indicates that forces between two objects are equal in magnitude and opposite in direction. When object A exerts a force on object B, object B reciprocates with an equal and opposite force on object A.
Step-by-step explanation:
According to Newton's third law of motion, when object A applies a force to object B, option b is correct: The force object A applies to object B has the same magnitude but is in the opposite direction as the force object B applies to object A. This law highlights that action and reaction forces are equal and opposite. This fundamental principle is critical in understanding how forces interact in various physical systems, including simple mechanics and complex engineering structures.