**A service provider is using multicast flows to provide streaming video content to its customers. Video streams are sometimes interrupted, and network instability is determined to be the cause. Which action should the service provider take to decrease the burden on the router resources in an unstable unicast routing environment?
A. Reduce the volume of query messages.
B. Tune the RPF backoff
C. i Increase the PIM hello hold timers.
D. Filter unnecessary SA messages.
