Pink boll worm is a pest of :

The correct answer is (b). Pink bollworm is a pest of cotton. It is a major pest of cotton in India and other parts of the world. It is a small, white moth with a pink band on its abdomen. The larvae of the pink bollworm feed on the cotton bolls, causing significant damage to the crop.

Soyabean (a) is a legume that is grown for its edible beans. It is a major source of protein and oil in the human diet. Bamboo (c) is a grass that is used for construction, furniture, and papermaking. Sugarcane (d) is a grass that is used to make sugar.

Pink bollworm is not a pest of soyabean, bamboo, or sugarcane. It is a pest of cotton only.