Final answer:
The true statement is that when using change streams, the aggregation framework command is used to filter the events being monitored, not the find command.
Step-by-step explanation:
The statement that is true regarding change streams is: a) When using change streams, it is important to use the aggregation framework command to filter the events that are being monitored. Change streams allow applications to access real-time data changes without the complexity and risk of tailing the oplog. Applications can use the aggregation framework to filter and modify the change events to subscribe to just the changes they are interested in.