Which two actions should you use to tune the GET VPN to meet the bank requirements?

You are consultant network designer for a large GET VPN deployment for a large bank with International coverage. Between 1800 and 2000 remote locations connect to the central location through four hubs using an MPLS backbone and using two keys servers. The bank is concerned with security and replay attacks.

Which two actions should you use to tune the GET VPN to meet the bank requirements? (Choose two)
A . Increase the cryptographic key size.
B . Replace unicast rekey with multicast rekey.
C . Reduce the SAR clock interval duration
D . Increase the TEK and KEK lifetime.
E . Reduce the Dead Peer Detection periodic timer.

Answer: B,C