Regarding GRE Over IPSec, which of the following statements is wrong?
A . IP header added in the IPSec encapsulation process is the source IP address of the interface to which the IPSec gateway applies the IPSec policy. The destination address is the address of the interface to which the IPSec policy is applied in the IPSec peer.
B . The data flow that IPSec needs to protect is the data flow from the GRE starting point to the GRE destination.
C . IP header added in the GR encapsulation process is the source address of the GRE tunnel, and the destination address is the destination address of the GRE tunnel.
D . When GRE over IPSec is used between gateways, IPSec encapsulation is performed before GRE encapsulation.
Answer: D