In his hometown, people asked of Jesus, 'Isn't this the ___'s son?'

Answer: Carpenter

In his hometown people asked, 'Isn't this the carpenter's son?' Mark 6:3 even calls Jesus himself 'the carpenter.'

““Isn’t this the carpenter’s son? Isn’t His mother’s name Mary, and aren’t His brothers James, Joseph, Simon, and Judas?”— Matthew 13:55 (BSB)