Which of the following always causes an object to change its velocity?

• If more forces began to act on an object
• If fewer forces began to act on an object
• If the forces acting on an object are equal in magnitude and opposite in direction
• If the forces on an object became unbalanced

All of these options can cause a change in an object's velocity except for "If the forces acting on an object are equal in magnitude and opposite in direction". In this scenario, the forces cancel each other out and there is no resultant force to cause a change in velocity.