Which one of the following deserts is famous for its deposits of nitrates?

Atacama deserts is famous for its nitrate deposits. The desert is littered with approximately 170 abandoned nitrate (or “saltpetre”) mining towns, almost all of which were shut down decades after the invention of synthetic nitrate in Germany at the turn of the 20th century. The towns include Chacabuco, Humberstone, Santa Laura, Pedro de Valdivia, Puelma, María Elena, and Oficina Anita.