The pre-colonial Yoruba political system was headed by an Oba whose powers were checked by which of the following councils?

In the Oyo Empire, the Alaafin's powers were checked by the Oyo Mesi, a council of seven kingmakers led by the Bashorun, and the Ogboni society, which handled matters relating to the earth deity and served as a judicial body. The Ekpe society was associated with the Efik, not the Yoruba, and the Ekitiparapo was a military alliance, not a council.