The answer is Kerala.
Kerala is the only state in India that is not a part of the Hindi belt. The Hindi belt is a region in India where Hindi is the primary language spoken. The other four states in the question are all part of the Hindi belt.
Kerala is also the only state in India that has a majority Christian population. The other four states in the question are all Hindu-majority states.
Kerala is also the only state in India that has a matrilineal system of inheritance. In a matrilineal system, property and inheritance are passed down through the female line. The other four states in the question are all patrilineal systems.
Kerala is also the only state in India that has a very high literacy rate. The literacy rate in Kerala is 94%, which is the highest in India. The literacy rates in the other four states in the question are all below 80%.
Kerala is also the only state in India that has a very low population density. The population density in Kerala is 860 people per square kilometer, which is the lowest in India. The population densities in the other four states in the question are all above 1,000 people per square kilometer.