Final answer:
Option a)Random Early Detection (RED) is the congestion avoidance method that drops packets if network congestion is detected but does not use IP precedence to determine packet priority.
Step-by-step explanation:
The congestion avoidance method that drops packets when network congestion is detected but does not use IP precedence to determine packet priority is called a)Random Early Detection (RED).
RED works by monitoring the average queue size in a network router. If the queue size exceeds a configured threshold, RED randomly drops packets to signal congestion to the sending host. This random dropping helps to prevent global synchronization and allows the network to self-regulate.
Overall, RED provides a proactive congestion control mechanism by selectively dropping packets, which makes it an effective method for managing network congestion.