Which role for the new user is correct?

An engineer manages a Cisco Intrusion Prevention System via IME. A new user must be able to tune
signatures, but must not be able to create new users. Which role for the new user is correct?

A.
service

B.
operator

C.
administrator

Explanation:
http://www.cisco.com/c/en/us/td/docs/security/ips/7-
0/command/reference/cmdref/crIntro.html