Which Cisco IPS appliance signature engine uses signature events as input to correlate different signatures into a higher level event?

A.
Atomic signature engine

B.
Service signature engine

C.
Meta signature engine

D.
Sweep signature engine

E.
Multistring signature engine

F.
Normalizer signature engine

Explanation:
http://www.cisco.com/en/US/docs/security/ips/6.1/configuration/guide/cli/cli_signature_engines.
html#wp1014660