When considering the three VoIP design models single site, centralized multisite, and distributed multisite which question below would help to eliminate one of these questions?

A.
Will the switches be required to provide inline power?

B.
Will users need to make off site calls, beyond the enterprise?

C.
Will users require applications such as voice mail and interactive voice response?

D.
Are there users whose only enterprise access is via a QoS-enabled WAN?

Explanation:
VoIP designing should consider how users are connecting to campus.

Link: http://www.net130.com/tutorial/cisco-
pdf/Cisco_%20IP%20Telephony%20Network%20Design_Guide.pdf