Choose the element that differentiates the Cisco SBCS solution

Choose the element that differentiates the Cisco SBCS solution from the competing Avaya IP Office and Nortel BCM 50 solutions.

A.
SBCS providesPoE through a modular upgrade.

B.
SBCS supports more analog trunks than the competitors.

C.
Only SBCS provides bundled conference calling.

D.
Only SBCS provides a wireless option.