To determine the correct ascending order of Indian states by their installed capacity of renewable energy as of December 2025, we need to understand the state of renewable energy development in India. The options provided are:

• Gujarat, Rajasthan, Tamil Nadu, Maharashtra
• Karnataka, Maharashtra, Rajasthan, Gujarat
• Tamil Nadu, Maharashtra, Rajasthan, Gujarat
• Karnataka, Maharashtra, Gujarat, Rajasthan

Let's explore these options considering India's progress in renewable energy projects:

1. Karnataka: Karnataka has continually been at the forefront of renewable energy development in India, especially in solar and wind power, making it a leading state in installed renewable energy capacity.
2. Maharashtra: As one of the largest states in India, Maharashtra has made significant strides in renewable energy, particularly in solar and wind, though not as advanced as some of the leading states like Karnataka.
3. Rajasthan: Known for its vast desert terrain, Rajasthan has a high solar energy potential. Its renewable energy capacity has been expanding rapidly, making it one of the top states in India in terms of installed capacity, especially solar power.
4. Gujarat: Like Rajasthan, Gujarat has been capitalizing on solar energy potential and has a robust wind energy sector, driving significant growth in renewable energy capacity.

Based on the above analysis, the correct ascending order of states according to their installed capacity of renewable energy as of December 2025 would be:

1. Karnataka
2. Maharashtra
3. Rajasthan
4. Gujarat

Thus, the correct option is: Karnataka, Maharashtra, Rajasthan, Gujarat.