The correct answer is: a) Rice
Rice is the primary Kharif crop of Punjab. Kharif crops are those that are grown during the rainy season, which in Punjab is from June to September. Rice is a water-intensive crop, and the state receives an average of 700 mm of rainfall during the Kharif season. This makes it ideal for growing rice.
Wheat is the primary Rabi crop of Punjab. Rabi crops are those that are grown during the winter season, which in Punjab is from October to March. Wheat is a dry-land crop, and the state receives an average of 250 mm of rainfall during the Rabi season. This makes it ideal for growing wheat.
Maize is a cereal crop that is grown in both Kharif and Rabi seasons. It is a drought-tolerant crop, and can be grown in areas with low rainfall. However, it is not as popular as rice or wheat in Punjab.
Cotton is a fiber crop that is grown in both Kharif and Rabi seasons. It is a water-intensive crop, and requires a lot of irrigation. However, it is not as popular as rice or wheat in Punjab.
In conclusion, the primary Kharif crop of Punjab is rice.