Correct option is B
Auxin is a plant hormone that plays a key role in root initiation.
It stimulates the formation of adventitious roots from cuttings and other plant parts.
Synthetic auxins like Indole-3-butyric acid (IBA) and Naphthalene acetic acid (NAA) are widely used in rooting powders.
Auxins also promote cell elongation and differentiation in plants.