Which body is responsible for enforcing financial decisions issued by a competent decision-making body?

The correct answer is that the player's new association is responsible for enforcing financial decisions issued by a competent decision-making body. When a player transfers to a new club, that club's association takes on the responsibility of ensuring compliance with financial obligations that may arise from decisions such as transfer fees or contractual agreements that have been established by relevant governing bodies. This is essential because the association has the authority to implement and enforce the regulations and obligations outlined by these financial decisions within its jurisdiction.

On the other hand, the other options do not directly fulfill this specific role. The Court of Arbitration for Sport primarily serves as an appellate body to resolve disputes and does not handle enforcement of financial decisions. The FIFA Disciplinary Committee is involved in disciplinary actions rather than enforcement of financial decisions. Lastly, the association of the body that issued the decision does not typically have a direct role in enforcing decisions, as it is the association of the receiver (the player's new club) that takes on that responsibility.