Which one of the following statements is NOT correct ?

Statement A is NOT correct because Madhya Pradesh is the second largest state in India by area, not the fourth. According to official government data (Census of India), the top four states by geographical area are:

• Rajasthan: 1st (approx. 342,239 sq km)
• Madhya Pradesh: 2nd (approx. 308,245 sq km)
• Maharashtra: 3rd (approx. 307,713 sq km)
• Uttar Pradesh: 4th (approx. 240,928 sq km)

The other statements are correct: the Hornbill Festival is a famous cultural event in Nagaland; Gujarat typically contributes around 8% (specifically 7.9% in various economic reports) to India's National GDP; and Telangana is indeed located on the Deccan Plateau in the central-southern stretch of the Indian peninsula.