The correct option is C 1930
ICBN, "International Code of Botanical Nomenclature”, is the collection of rules of scientific nomenclature of plants and was first proposed by Sprague, Hitchcock, Green (1930) but was accepted in 1961. During 12th International congress, Leningrade 1975, ICBN was revised. The revised form was republished in 1978. Thus, ICBN was proposed in 1930. Thus, the correct answer is option A.