Your network contains a single Active Directory domain. All domain controllers run Windows Server 2008 R2. There are 1，000 client computers that run Windows 7 and that are connected to managedswitches. You need to recommend a strategy for network access that meets the following requirements： èUsers are unable to bypass network access restrictions. èOnly client computers that have up-to-date service packs installed can access the network. èOnly client computers that have up-to-date anti-malware software installed can access the network. What should you recommend？（）
- AImplement Network Access Protection （NAP） that uses DHCP enforcement.
- BImplement Network Access Protection （NAP） that uses 802.1x enforcement.
- CImplement a Network Policy Server （NPS）， and enable IPsec on the domain controllers.
- DImplement a Network Policy Server （NPS）， and enable Remote Authentication Dial-In User Service （RADIUS） authentication on the managed switches.