Why does Sachar include this information in the flashback?

O to show that Elya has nothing to do with the bad luck

Stanley is experiencing

O to show that Stanley needs to find Madame Zeroni in

order to lift the curse

O to show that the Yelnats' curse is tied to Elya's betrayal

of Madame Zeroni

O to show that Elya's bad luck caused his wife to leave

him for another man