Which four requirements are mandatory to enable a mixed mode Cisco Unified CM cluster? (Choose four.) 

Answer options:

A. Cisco CTL Provider Service activated and enabled
B. Cisco Certificate Authority Proxy Function activated and enabled
C. Cisco Trust Verification activated and enabled
D. Cisco CTL client
E. a minimum of one USB e-token
F. a minimum of two USB e-token
G. a minimum of one soft e-token

ABDF