Explanation:

Sure, here’s an explanation for each option:

- Option 1: 50 percent — This is too low based on most rural energy use surveys in India.

- Option 2: 75 percent — Closer, but still a bit less than real figures in recent studies.

- Option 3: 80 percent — This is very close to the official figures. According to government reports (such as National Sample Surveys and Census 2011), about 80% of rural households depend on bio-fuels like wood, dung, and crop residue for cooking.

- Option 4: 90 percent — This is higher than recent estimates. In the past (decades ago), it was up to 90%, but recent statistics show a slight reduction as more move towards LPG or other fuels.

- Correct Answer: Option 3 – 80 percent.

- Bio-fuel usage remains high due to limited access or affordability of cleaner fuels.

- Health and environmental impacts from using bio-fuels are significant concerns.