Why is NTP an important component when implementing IPSec VPN in a PKI environment？（）

• A、 To ensure the router has the correct time when generating its private/public key pairs.
• B、 To ensure the router has the correct time when checking certificate validity from the remote peers
• C、 To ensure the router time is sync with the remote peers for encryption keys generation
• D、 To ensure the router time is sync with the remote peers during theDH exchange
• E、 To ensure the router time is sync with the remote peers when generating the cookies during IKE phase 1