Organogenesis or morphogenesis in tissue culture is controlled/regulated by phytohormones. The credit of this important discovery goes to Guha and Maheswar (1964), Calvin and Benson (1894), Skoog and miller (1957), and Halperin and Wetherail (1964).

Organogenesis or morphogenesis is the regeneration of an organ from the undifferentiated mass of cells, which is best known as a callus. Skoog and Miller (1957) showed that an appropriate concentration of phytohormone auxin and cytokinin stimulates the morphogenesis or organogenesis. A higher concentration of auxin with cytokinin promotes cell division in shoots, while a higher concentration of cytokinin with auxin stimulates cell division in roots. So, the correct answer is option A.