Step 1: Understanding the Question:
This question asks you to match four CGIAR (Consultative Group on International Agricultural Research) centers with the city where each has its headquarters.
Step 2: Key Formula or Approach:
Each CGIAR center is a separate international research body with its own fixed headquarters location, so this is a direct recall match rather than a calculation.
Step 3: Detailed Explanation:
(A) International Institute of Tropical Agriculture (IITA): headquartered in Ibadan, Nigeria, matching definition (IV). IITA focuses on tropical crops such as cassava, maize and cowpea across sub Saharan Africa.
(B) International Livestock Research Institute (ILRI): headquartered in Nairobi, Kenya, matching definition (I). ILRI works on livestock research to improve food security in developing countries.
(C) International Water Management Institute (IWMI): headquartered in Battaramulla, Sri Lanka, matching definition (II). IWMI focuses on water and land management for agriculture.
(D) International Center for Agricultural Research in the Dry Areas (ICARDA): headquartered in Beirut, Lebanon, matching definition (III). ICARDA works on crop and livestock production suited to dry, non tropical areas.
Step 4: Final Answer:
The correct matching is (A)-(IV), (B)-(I), (C)-(II), (D)-(III), which corresponds to option (3).