Ben is explaining to his dad what unbalanced forces are. He uses arm wrestling as an example. Which of the following is the best explanation that Ben can use?

If Ben and his dad push their arms with an equal force, the forces are unbalanced.
Since Ben and his dad have different weights, the forces are unbalanced.
If Ben and his dad push their arms with different forces, the forces are unbalanced.
If Ben and his dad's hands do not change positions at the start of the game, the forces are unbalanced.