[单选题]13、 Which Diffie-Hellman group must be used for a tunnel establishment between an ASA device and the Cisco IPsec VPN client to be successful?为了在ASA设备和Cisco IPSec VPN客户端之间成功地建立隧道，必须使用哪种Diffie-Hellman组?
A. 1
B. 2
C. 3
D. 5