The plant hormone responsible for the triple response is:

Correct option is C

Ethylene induces the triple response in plants, which includes:
Inhibition of stem elongation
Radial swelling of stems
Horizontal growth of shoots
(a) Auxin: Promotes cell elongation.
(b) Gibberellin: Promotes growth.
(d) Cytokinin: Promotes cell division.
Important Point: Ethylene is also known as the ripening hormone in fruits.