The integrated services routing architecture provides the performance， availability， and reliabilityneeded to scale mission-critical business applications in the most demanding environments.Which statement best describes the benefits of Cisco Integrated Services Routers？（）

• A、 ISRs provide threat defense against attacks from hackers and viruses that can occur in thenetwork.
• B、 ISRs provide the framework to integrate and extend wired and wireless networks
• C、 ISRs provide concurrent security， voice， data， wireless， and application optimization services.
• D、 ISRS provide the common fabric， functionality， and CLI across the network.