The correct answer is: A. Rice
Rice is the most important cereal crop in Bihar, accounting for over 80% of the state’s cereal production. The average per hectare yield of rice in Bihar is 2.5 tonnes, which is higher than the national average of 2.2 tonnes.
Wheat is the second most important cereal crop in Bihar, accounting for about 10% of the state’s cereal production. The average per hectare yield of wheat in Bihar is 2.0 tonnes, which is lower than the national average of 3.0 tonnes.
Maize is the third most important cereal crop in Bihar, accounting for about 5% of the state’s cereal production. The average per hectare yield of maize in Bihar is 1.5 tonnes, which is lower than the national average of 2.0 tonnes.
Barley is a minor cereal crop in Bihar, accounting for less than 1% of the state’s cereal production. The average per hectare yield of barley in Bihar is 1.0 tonnes, which is lower than the national average of 1.5 tonnes.
Therefore, rice has the highest per hectare yield in Bihar.