In a deployment using standalone access points， clients set up to authenticate with eap-peap or eap-cisco wireless （cisco-leap） cannot authenticatE.  when you inspect the failed attempts report on the cisco secure acs， you find this error： "unknown network access server nas."  Which problem may have caused this failure？（）

• A、misconfigured ip address of the aaa server on the access point
• B、misconfigured eap type on the access point
• C、misconfigured ip address of the access point on the aaa server
• D、misconfigured eap type on the aaa server