Increasing the wireless coverage might not directly address the high number of clients disconnecting if the area coverage is already sufficient. Adjusting the data rates requires assessing if slow data rates are the actual cause of disassociation, which is not directly implied. Replacing the antenna would depend on whether the existing ones are faulty or unsuitable for the environment, which isn't suggested by the given scenario. Adding an additional access point addresses the issue by reducing the load on a single access point, thus likely decreasing the frequency of disconnections during peak hours. This aligns with managing network congestion and ensuring adequate service delivery for all connected clients.