Final answer:
Cart X experienced a greater magnitude of impulse because it experienced the greater change in velocity.
Step-by-step explanation:
The cart that experiences a greater magnitude of impulse is determined by the change in velocity. Impulse is defined as the change in momentum of an object, and momentum is the product of an object's mass and velocity.
Based on the information provided, if Cart X experienced a greater change in velocity compared to Cart Y, then Cart X would have a greater magnitude of impulse. Therefore, option A is correct: Cart X experienced a greater magnitude of impulse because it experienced the greater change in velocity.