Which statement is TRUE regarding Caliph al-Mahdi and the problem of succession in the Abbasid dynasty?
a. He appointed one of his sons to succeed him.
b. He failed to resolve the problem of dynastic succession with disastrous results.
c. He specified the rule of primogeniture, the succession of the oldest son.
d. He accepted the radical proposition that only a man of demonstrable Islamic purity should succeed.
e. He accepted the Shi'a doctrine that only the person with the most direct relationship to Muhammad should succeed.
Answer: B