Users of a site-to-site VPN are reporting performance problems. The VPN connection employsIPSec and GRE and traverses several Ethernet segments. The VPN packets are being fragmented as they traverse the links. What would be two methods to overcome this problem？（）

• A、 Employ path MTU discovery.
• B、 Set the MTU higher than 1500 bytes.
• C、 Turn off pre-fragmentation for IPSec.
• D、 Set the MTU value to 1400 bytes.