The correct option is (c) Gibberellins.
Explanation:
Vernalisation refers to the application of low temperature to moistened seeds and young plants, causing shortening of vegetative phase and initiation of reproductive phase.
Chailakhyan (1968) reported that under long-day conditions vernalin hormone turn into gibberellin and thus, in some plants, the requirement for vernalisation is overcome by gibberellins.
