Which hormone promotes internode/petiole elongation in deep water rice?

Deep water rice is a variety of rice that grows in flooded or deep water conditions. Ethylene is a plant hormone that promotes internode and petiole elongation in deep water rice, allowing the plant to keep its leaves above the water surface. Ethylene is produced by the plant in response to flooding, and it diffuses throughout the plant to promote elongation growth. 

(1) 2, 4-D is widely used as herbicide. 

(2) Gibberellic acid (GA₃) was one of the first gibberellins to be discovered and remains the most intensively studied
form. It produces a wide range of physiological responses in the plants. 

(3) Kinetin does not occur naturally in plants. They help in rapid cell division.