The correct option is A Morgan
Gene theory: It is one of the basic principles of biology. The main concepts of this theory is that traits are passed from parents to offspring through gene transmission. Genes are located on chromosomes and consist of DNA. They are passed from parent to offspring through reproduction. Morgan allied himself with those embryologists who thought the control of development lay within the cytoplasm, while Wilson allied himself with Theodor Boveri, one of the biologists who felt that the nucleus contained the instructions for development.