Explanation:

- Kerala has consistently held the top position for literacy rates in India. With extensive educational reforms, the state boasts a rate exceeding 90%.

- Mizoram also performs well in literacy due to the emphasis on education, particularly among tribal communities. It usually ranks among the top states.

- Bihar historically has lower literacy rates compared to many other states, although efforts to improve education have led to gradual improvements.

- None of these implies neither of the mentioned states has the highest literacy rate, which is incorrect here as Kerala is recognized for its educational achievements.

Correct Answer: Option 2: Kerala