- Statement I is correct because wheat is indeed grown in the western parts of the Indo-Gangetic plains in India, particularly in the states of Punjab and Haryana.
- Statement II is incorrect because wheat is not confined to monsoonal areas. It is cultivated in areas with cooler climates as well, such as the Indo-Gangetic plains and parts of northern China.
- Statement III is correct because millets are grown in dry areas, particularly in the western and southern parts of India, due to their tolerance to drought conditions.
- Statement IV is correct because wheat, soybean, and other crops are widely cultivated in northern China, especially in regions like the North China Plain.
Thus, the correct statements are I, III, and IV, which makes option (C) the correct choice.