Explanation:

- The National Research Centre on Seed Spices focuses on the research and development of seed spices like cumin, coriander, and fenugreek.

- Option 1: Doomara, Ajmer - This is not the correct location for the National Research Centre on Seed Spices.

- Option 2: Mandore, Jodhpur - Known for its historical significance, Mandore is not the location of the research center.

- Option 3: Beechwal, Bikaner - Although Bikaner is prominent in agriculture, it's not home to this specific research center.

- Option 4: Durgapura, Jaipur - This is the correct location. The center is situated in this region, known for agricultural research facilities.