A technique of androgenic haploid formation was developed by Carlson et.al. Guha and Maheshwari Halperin and Wetherell Steward et.al.

The correct option is 2.
A doubled haploid (DH) is a genotype formed when haploid cells undergo chromosome doubling. Artificial production of doubled haploids is important in plant breeding.

Haploid cells are produced from pollen or egg cells or from other cells of the gametophyte, then by induced or spontaneous chromosome doubling, a doubled haploid cell is produced, which can be grown into a doubled haploid plant. If the original plant was diploid, the haploid cells are monoploid, and the term doubled monoploid may be used for the doubled haploids. Haploid organisms derived from tetraploids are sometimes called dihaploids (and the doubled dihaploids are tetraploid).