问题：

[单选题]43、 Which advanced hardware client feature, if enabled, allows a Cisco Aironet access point at the remote site to contact a RADIUS server at the VPN head-end site when Easy VPN advanced authentication methods have been deployed?当配置Easy VPN高级的验证方法时，在启动下面的哪一个高级硬件客户端特性后，它允许远端站点的Cisco Aironet access point去联系位于VPN头端站点的RADIUS服务器?
A. Device Pass-Through 设备直通
B. LEAP Bypass LEAP旁路
C. Network Extension mode 网络扩展模式
D. Client mode 客户端模式