Rapid Progress in the Elucidation of Signal Transduction Pathways in Plant

Rapid progress in the elucidation of signal transduction pathways in plant hormone action has been made using the model plant, Arabidopsis thaliana.Genetic screens involve the following steps:
1.Mapping and cloning of a gene
2) Selection of a phenotype
3) Exposure of seeds to a chemical mutagen
4) Germination of the seeds and identification of mutants
Which of the following shows these steps in their proper sequence?"

A) 2, 1, 3, 4
B) 1, 2, 4, 3
C) 2, 3, 4, 1
D) 1, 2, 3, 4
E) 3, 2, 4, 1