[Recently,telecommunication carriers has been building All-IP core networks in orderto effectively support various kinds of fixed and mobile broadband services,such as upanddown-loading Youtube and SNS（Social Networking Services）with rich video file,as wellas broadband mobile Internet services.Sucb All-IP network is called NGN（Next GenerationNetwork）,which guarantees secure authentication and QoS such as the bandwidth and thedelay.From the service point of view,convergence of fixed and mobile communications,known as FMC（Fixed Mobile Convergence）is becoming a key in creating new services andexpanding the market.]
From the paragraph above,we can see that（1）can be defined as a network that caneffectively support various kinds of fixed and mobile broadband services,with guaranteedQoS in terms of（2）and etC.And the key to develop new services and gain larger marketshare should be（3）._________.

A.All-IP access network

B.broadband network

C.NGN

D.social network