Which of the following best explains why Ivan IV created the oprichnina during his reign?

Ivan was not popular in cities like Novgorod where people rose up against his rule.
Ivan no longer had a good relationship with the Russian Orthodox Christian Church and wanted to destroy it.
Ivan IV was struggling against the boyars and wanted to limit their power .
Ivan IV had been overthrown by the boyars and was trying to regain his power .

The best explanation for why Ivan IV created the oprichnina during his reign is that he was struggling against the boyars and wanted to limit their power.