Which solution is least effective for managing network congestion?

Disabling user accounts temporarily is the least effective solution for managing network congestion because it addresses the symptom rather than the root cause of congestion. While it may reduce the number of active users at any given time, it does not improve the overall capacity or efficiency of the network infrastructure.

In contrast, upgrading network hardware enhances the capacity and performance of the network, enabling it to handle more data traffic efficiently. Implementing Quality of Service (QoS) prioritizes critical data traffic, ensuring that important applications receive the bandwidth they need during peak times. Encouraging off-peak usage spreads the network load over a longer period, allowing for better utilization of available bandwidth when traffic is lighter. Each of these approaches provides a more comprehensive strategy to improve network performance and manage congestion effectively.