What was the major cause of the first civil war in early islamic society?

The first Islamic civil war or  "Fitna " happened in the 7th century, after the Caliph Uthman Ibn Affan´s assassination (d. 656). According to Islamic tradition, close relatives were the ones to take responsibility for avenging the assassinated´s death so both his favorite wife, Aisha and his brother Ali got into a dispute over who would avenge Uthman Ibn Affan.

Ultimately the war ended by the signing a treaty in 661.

here you go hope it heps "horace mann"

your answer would be (a)