Step 1: Understand the question.
We need the Indian state team that won the Ranji Trophy in the 2025 to 2026 season. The Ranji Trophy is India's top domestic first-class cricket title.
Step 2: Recall the nature of the tournament.
State teams play against each other across the season, and one team lifts the trophy in the final. So we must pick the winning state.
Step 3: Look at the options.
The choices are Tamil Nadu, Jammu and Kashmir, Maharashtra, and Karnataka. All are state cricket teams, so we must recall the actual champion.
Step 4: Identify the champion.
In the 2025 to 2026 season the title was won by Karnataka.
Step 5: Confirm by elimination.
The other three states did not lift the trophy that season, so they are distractors. Only Karnataka fits.
Step 6: Match with the options.
The fourth option is correct.
\[ \boxed{\text{Karnataka}} \]