Doctors examine her husband’s sperm and analysis indicates that the dynein arms are absent from the flagella?

No, thats not the case Angel of Sin. Look more closely at the answer choice. It says "preventing the sperm from SYNTHESIZING enough energy to swim" meaning synthesizing ATP. As long as the sperm cells have intact mitochondria, there is plenty of energy in the sperm cells in the form of ATP. Dynein CONVERTS the energy of ATP into motion. So the sperm cells won't be able to use ATP to move, meaning they won't be able to swim.