which port is the IKE SA established?

Refer to the Exhibit.

[A] establishes an IPsec tunnel with [B]. The NAT device translates the IP address 1.1.1.1 to
2.1.1.1.On which port is the IKE SA established?

A.
TCP 500

B.
UDP 500

C.
TCP 4500

D.
UDP 4500