So rule out the legend theory. That leaves 4. The only other alternative is that Jesus spoke the truth. Rule out calling him a liar, rule out self-deception, and rule out that all his followers perpetrated a huge hoax rather rapidly, within the lifetime of those who personally knew Jesus, and the only alternative is to conclude that the man was who he said he was. Now, anyone can make claims.
Talk is cheap.
Unlike Elvis sighters and JFK Jr. groupies, Jesus had the credentials to back up his claim. His credentials, very briefly, were these. First, Jesus' moral character coincided with his claims. We know of people who claim to be deity, but they are belied by their characters. He is unique.