Which one of the following groups of plants was domesticated in the ‘New World’ and introduced into the ‘Old World’?

The correct answer is A: tobacco, cocoa and rubber. All three were domesticated in the Americas and carried to the Old World after 1492. Tobacco came from Nicotiana species in the Americas and spread to Europe and Asia. Cocoa (Theobroma cacao) was domesticated in Mesoamerica and the Amazon basin and later grown in West Africa. Rubber (Hevea brasiliensis) was native to the Amazon and was taken to Southeast Asia, where it became a major plantation crop.

Why the others fail: coffee is native to Ethiopia and the Arabian side of the Red Sea, so it is an Old World plant. Sugarcane was domesticated in New Guinea and South Asia. Wheat comes from the Fertile Crescent. Cotton is the tricky one. Old World cotton (Gossypium arboreum and G. herbaceum) was grown in India and Africa long before 1492, so cotton cannot be treated as a New World-to-Old World transfer. That rules out B, C and D.

Core concept: the Columbian Exchange, the two-way movement of crops, animals and diseases after 1492. It links to Mains GS-I on world history and the plantation economy, and to the spread of slavery-linked cash crops.

Trap: aspirants see 'cotton' in option B and pick it as a New World crop because the Mexican species G. hirsutum is one. The question is about crops that moved from the Americas to the Old World, and cotton was already present there.