RFC 2828 (Internet Security Glossary) defines IKE as an Internet, IPsec, key-establishment protocol (partly based on OAKLEY) that is intended for putting in place authenticated keying material for use with ISAKMP and for other security associations, such as in AH and ESP.
The following are incorrect answers:
SKIP is a key distribution protocol that uses hybrid encryption to convey session keys that are used to encrypt data in IP packets.
The Key Exchange Algorithm (KEA) is defined as a key agreement algorithm that is similar to the Diffie-Hellman algorithm, uses 1024-bit asymmetric keys, and was developed and formerly classified at the secret level by the NSA.
Security Association Authentication Protocol (SAAP) is a distracter.
Reference(s) used for this question: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.