Answer : 4. "Parabolic "
Explanation :

Parabolic Sand Dune-

1. Parabolic Sand Stupa is also called Parabolic Sand Stupa.

2. Sand stupas like Barkhan's viparita or women's hair pin (clip) are called parabolic sand stupas.

3. Parabolic sand stupas in Rajasthan are generally found in Jaisalmer, Bikaner, Barmer and Jodhpur.

4. Parabolic sand stupas are found most in Rajasthan because parabolic sand stupas are found in all the desert districts.