What Was the Experimental Purpose of the Preliminary Genetic Screening

Multiple Choice

What was the experimental purpose of the preliminary genetic screening performed in which Nüsslein-Volhard and Wieschaus exposed adult fruit flies to treatments that would cause mutations in their offspring?

A) to evaluate the mutagenic properties of varied treatments
B) to discover the bicoid gene
C) to generate two-tailed fruit-fly embryos
D) to identify fruit flies with mutations in genes that control fruit-fly development