Development of shoot and root in tissue culture is determined by

Answer: Option A

Development of shoot and root in tissue culture is determined by cytokinin and auxin ratio.
The pioneering work has shown that a high auxin/cytokinin ratio induces root regeneration, whereas a low ratio promotes shoot induction.
High cytokinin-to-auxin ratios correlated with the shooty phenotype of transformed tissues propagated in vitro in the absence of added growth hormones.