Explanation:

- Paryushan Parv - This is the correct answer. The Shwetambar community celebrates it for eight days, while the Digambar community celebrates it for ten days. During this festival, Jains focus on fasting, forgiveness, and spiritual upliftment.

- Gyan Panchami - Celebrated five days after Diwali, it is a day dedicated to learning and knowledge. It is not an eight or ten-day festival.

- Kartik Purnima - This is a Hindu and Jain festival marked on the full moon day of the Kartik month. It is a one-day event and not relevant to the duration noted.

- Navpad Oli - Celebrated twice a year, it lasts nine days each time and is focused on fasting and worshiping the Navapad, not matching the eight and ten-day criteria.