The National Diamond Institute is located at:

Surat

The correct answer is Option (1) - Surat

The National Diamond Institute is located in Surat, a city in the Indian state of Gujarat. Surat is renowned as a major hub for diamond cutting and polishing industries, contributing significantly to India's diamond trade. The institute plays a crucial role in providing education, training, and research facilities related to the diamond industry, fostering skill development and innovation in this sector.