Refer to the exhibit. What enterprise IP telephony deployment model is represented?()<br /> <img src="https://nimg.ppkao.com/2018-07/zhanglijun/2018072416060627546.jpg?sign=d84e7f4c0e98d0974e29b56d59277428&t=62d20fa4" />
A、core distribution access
B、multisite with centralized call processing
C、multisite with distributed call processing
D、clustering over WAN
E、PSTN-WAN
F、Enterprise Composite Model