In 2013-2014, Tripura won the first position in India for its success in

Concept: MGNREGA (the Mahatma Gandhi National Rural Employment Guarantee Act, 2005) guarantees at least 100 days of wage employment per rural household per year, and a state's implementation performance is measured nationally each financial year by the average number of person-days (mandays) of employment provided per household that worked under the scheme.

Application: In the financial year 2013-14, Tripura provided an average of about 88 person-days of employment per household that worked under MGNREGA, well above the national average of roughly 46 days that year, which placed the state first among all Indian states and Union Territories in MGNREGA implementation for 2013-14.

Cross-check: The other three options describe production sectors, not employment-guarantee performance. Tripura was not the national leader in paddy production (led that period by states such as West Bengal, Uttar Pradesh, and Punjab), fish production (led by states such as Andhra Pradesh and West Bengal), or cashewnut production (led by states such as Maharashtra, Andhra Pradesh, Odisha, and Karnataka).

Result: Tripura's first-place national ranking in 2013-14, referenced in the question, was for its MGNREGA implementation, confirmed by the state's official economic review and the exam's own answer key.