What event occurred in 712 in relation to Áed Róin's rule?

A. The sons of Becc Bairrche were defeated by the son of Bressal mac Fergusa
B. The Ulaid (Dal Fiatach) were overthrown and Dubthach mac Bécce was slain
C. Áed Róin was crowned king of the Dál nAraidi
D. The Ulaid (Dal Fiatach) were victorious in a battle against the Uí Echach Cobo
Answer: 