What is causing the IPsec problem in the phase 1 ?

An administrator added the following Ipsec VPN to a FortiGate configuration:

configvpn ipsec phasel -interface

edit "RemoteSite"

set type dynamic

set interface "portl"

set mode main

set psksecret ENC LCVkCiK2E2PhVUzZe

next

end

config vpn ipsec phase2-interface

edit "RemoteSite"

set phasel name "RemoteSite"

set proposal 3des-sha256

next

end

However, the phase 1 negotiation is failing. The administrator executed the IKF real time debug while attempting the Ipsec connection.

The output is shown in the exhibit.

What is causing the IPsec problem in the phase 1 ?
A . The incoming IPsec connection is matching the wrong VPN configuration
B . The phrase-1 mode must be changed to aggressive
C . The pre-shared key is wrong
D . NAT-T settings do not match

Answer: C