Which two are valid suppression types on a Cisco Next Generation Intrusion Prevention System?

While traffic can be filtered by port, 'Port' is not a primary, explicit suppression type in Cisco NGIPS policies in the same way as Rule or Source.

Rule suppression allows you to stop generating events for a specific intrusion rule, which is useful for mitigating false positives from a particular signature. C. Source suppression enables you to suppress events originating from a specific source IP address, useful when a known benign source triggers alerts.

Application suppression is not a standard, explicit suppression type in Cisco NGIPS compared to Rule, Source, or Destination.

Protocol suppression is not a standard, explicit suppression type in Cisco NGIPS for event suppression.