The correct answer is B. Kshatriya Princes.
The religious movements of Buddhism and Jainism were led by Kshatriya Princes. The Kshatriyas were the second highest caste in the Hindu caste system, and they were the warriors and rulers of society. They were the ones who had the power to change the social order, and they were the ones who were most likely to be dissatisfied with the existing order.
The Buddha was born into a Kshatriya family, and he was raised to be a warrior. However, he became disillusioned with the violence and suffering of the world, and he renounced his wealth and position to seek enlightenment. He eventually achieved enlightenment under the Bodhi tree, and he began to teach others the path to enlightenment.
Mahavira was also born into a Kshatriya family, and he was raised to be a warrior. However, he became disillusioned with the violence and suffering of the world, and he renounced his wealth and position to seek liberation from the cycle of rebirth. He eventually achieved liberation, and he began to teach others the path to liberation.
Both the Buddha and Mahavira were charismatic leaders, and they attracted many followers. Their teachings spread throughout India, and they had a profound impact on Indian society. Buddhism and Jainism are still practiced today, and they have millions of followers around the world.
The other options are incorrect. Option A, Sudras, is incorrect because the Sudras were the lowest caste in the Hindu caste system. They were the servants and laborers of society, and they had very little power to change the social order. Option C, Vaisyas, is incorrect because the Vaisyas were the third highest caste in the Hindu caste system. They were the merchants and traders of society, and they had some power to change the social order, but they were not as powerful as the Kshatriyas. Option D, Brahmins, is incorrect because the Brahmins were the highest caste in the Hindu caste system. They were the priests and scholars of society, and they had the most power to change the social order. However, they were not as likely to be dissatisfied with the existing order as the Kshatriyas were.