Final answer:
The commons in England during the Middle Ages was underused due to free riding, leading to overgrazing and the ruin of the pasture.
Step-by-step explanation:
The answer to whether the common land in England during the Middle Ages was used optimally is option A: The commons was underused due to free riding. In the Tragedy of the Commons, it is described how the lack of responsibility for the land led to overgrazing and the ruin of the pasture. Each herdsman had an incentive to add more cattle without taking on the responsibility of the damage caused by overgrazing. This resulted in the commons being underused.