Option d is the correct answer. Gautama Buddha did not nominate anyone for the leadership of the Buddhist Sangha after his death. The Buddha believed that the Sangha should be self-governing and that the leader should be elected by the monks. After the Buddha's death, a council was held to discuss the future of the Sangha. The council was presided over by Mahakassapa, one of the Buddha's closest disciples. The council decided that the Sangha should be led by a group of elders, called the Sangha Mahasabha. The Sangha Mahasabha is still the supreme authority in the Buddhist world. The members of the Sangha Mahasabha are elected by the monks and they are responsible for the overall well-being of the Sangha.