Which one of the following statements concerning research centres in India is not correct?

Introduction / Context:
India hosts numerous specialized research institutes related to biotechnology, forestry, ecology, and arid zone studies. Competitive exams often test whether you can correctly associate each institute with its city. This question lists four pairs and asks which one is not correct. Three of the pairings correctly match institutes to their locations, while one pairing assigns the institute to the wrong city. Identifying that incorrect pair requires precise factual knowledge of institutional locations.

Given Data / Assumptions:

• Rajiv Gandhi Centre for Biotechnology (RGCB) is a research institute in biotechnology.
• Central Arid Zone Research Institute (CAZRI) focuses on arid zone research.
• Centre for Social Forestry and Eco-Rehabilitation deals with social forestry and eco rehabilitation.
• Institute of Forest Productivity works on forestry productivity and related research.
• The options propose that these institutes are in Kolkata, Jodhpur, Allahabad or Prayagraj, and Ranchi respectively.

Concept / Approach:
The strategy is to recall or verify where each institute is located. The Rajiv Gandhi Centre for Biotechnology is based in Thiruvananthapuram in Kerala, not Kolkata, so any statement that places it in Kolkata is incorrect. CAZRI is indeed headquartered at Jodhpur in Rajasthan. The Centre for Social Forestry and Eco-Rehabilitation is located at Allahabad, now called Prayagraj, in Uttar Pradesh. The Institute of Forest Productivity is situated at Ranchi in Jharkhand. Therefore, three of the location pairings are correct, while the one linking RGCB to Kolkata is not.

Step-by-Step Solution:
Step 1: Examine option A. Rajiv Gandhi Centre for Biotechnology is widely known to be located in Thiruvananthapuram, Kerala, not in Kolkata. Therefore this statement is not correct. Step 2: Examine option B. Central Arid Zone Research Institute is headquartered at Jodhpur in Rajasthan and conducts research on arid and semi arid regions. This pairing is correct. Step 3: Examine option C. The Centre for Social Forestry and Eco-Rehabilitation operates out of Allahabad or Prayagraj in Uttar Pradesh. This statement is correct. Step 4: Examine option D. Institute of Forest Productivity is located at Ranchi in Jharkhand, which matches the information from forestry research networks. This statement is correct. Step 5: Since only option A misplaces the Rajiv Gandhi Centre for Biotechnology in Kolkata instead of Thiruvananthapuram, option A is the incorrect statement the question is asking for.

Verification / Alternative check:
You can verify through basic awareness of regional research hubs. Thiruvananthapuram in Kerala is a known centre for several advanced research institutions, including RGCB, while Kolkata is not cited as the base for this particular biotechnology centre. Jodhpur, located in Rajasthan s arid region, is logically suited for the Central Arid Zone Research Institute, which matches both geography and function. Allahabad or Prayagraj is recognized in forestry literature as hosting the Centre for Social Forestry and Eco-Rehabilitation. Ranchi is the site of the Institute of Forest Productivity under the national forestry research system. These consistent matches across sources confirm that only the first statement is incorrect.

Why Other Options Are Wrong (as incorrect choices):
Central Arid Zone Research Institute is located at Jodhpur: This is a correct pairing, so it cannot be the answer to a question that asks for an incorrect statement.

Centre for Social Forestry and Eco-Rehabilitation is located at Allahabad or Prayagraj: This is also a correct statement and therefore not the required incorrect one.

Institute of Forest Productivity is located at Ranchi: This fact is accurate, eliminating it from consideration as the incorrect option.

Common Pitfalls:
Some aspirants may confuse different biotechnology institutes or assume that any institute named after a national leader must be in a large metro like Kolkata or Delhi. Others may not have memorized the exact cities for forestry related institutes and could wrongly suspect one of the correct pairs. Another pitfall is not paying attention to the wording not correct and accidentally marking a correct statement. Reading the question carefully and revising a short list of institutes with their locations is essential to avoid these mistakes.

Final Answer:
The statement that is not correct is the one claiming that the Rajiv Gandhi Centre for Biotechnology is located at Kolkata, so the correct answer is “Rajiv Gandhi Centre for Biotechnology is located at Kolkata.”