A wired network connection is the most reliable and robust method for a multifunction printer in a busy office environment. It usually provides greater speed and does not suffer from interference like wireless connections might, which is crucial for handling heavy workloads and advanced features. Wired connections also enable central management through network management tools. Wireless connections may seem convenient, but they might not provide the necessary stability and performance for this scenario. USB would not allow network connectivity, and Bluetooth would not be appropriate due to its limited range and bandwidth.