I have asked this question from here twice and once I got answer like only message 3, another time they said none of them? Can u clarify the answer please

In this key establishment protocol, - A interacts with a trusted server T and a party B. - A and T share a symmetric key KA. and B and T share a symmetric key KBT. - T will choose a key k to be shared by A and B. - NA and NB are nonces chosen by A and B respectively. - We will write EK(x) to mean encrypting a message x using a symmetric key encryption algorithm E with key K. The protocol runs as follows: 1. AT:A,B,NA. 2. T A:EKNT(NA,B,k,EKT(k,A)). 3. AB:EKBr(k,A). 4. BA:Ek(NB). 5. AB:Ek(NB1). Which message(s), if any, provide confirmation to B that the key k is possessed by A ? None of them. Massage 1. Message 2. Message 3. Message 4. Messoge 5