The correct answer is 2 and 3 only.
Explanation:
1. Avoidance of extremities of penance and enjoyment: This was a principle followed by Buddhism, but not by Jainism. Jains believed in the concept of asceticism, and practiced extreme forms of penance and self-mortification.
2. Indifference to the authority of the Vedas: Both Buddhism and Jainism rejected the authority of the Vedas, which were considered the sacred texts of Hinduism.
3. Denial of efficacy of rituals: Both Buddhism and Jainism rejected the efficacy of rituals in achieving spiritual goals, and emphasized the importance of individual effort and self-realization.
Therefore, the correct answer is option 2 and 3 only.