Hormone responsible for growth of the root in micropropagation is
(a)Auxin
(b) Gibberellin
(c)Cytokinin
(d)Abscisic acid

Hint: -Plant Growth Regulators can be of a different chemical composition, for example, gases (ethylene), terpenes (gibberellic acid) or carotenoid derivatives (abscisic acid). They are also known as plant development substances, phytohormones or plant hormones

Complete answer:
Let’s discuss the question and find out the correct answer
-Auxins have a significant part in coordination of numerous development and social cycles in the vegetation's cycle and are basic for plant body improvement. Auxins promote root initiation and promote growth of pre-existing roots as well as adventitious roots In agriculture, auxins particularly NAA and IBA, are normally applied to invigorate root commencement in woody plants.

-Gibberellin is a plant development advertiser which assists with eliminating dwarfism and also promotes seed germination and inhibits seed dormancy.

-Cytokinins were found as kinetin. Kinetin doesn't happen normally however researchers later found a few characteristics (model – zeatin) and synthetic cytokinins. Common cytokinins exist in root apices and create shoot buds – regions where quick cell division happens.

- It builds the resistance of plants to various types of pressure and is, along these lines, called 'stress hormone.Important for seed improvement and maturation.It additionally prompts torpidity in seeds and encourages them withstand parching and other horrible development factors
So, the correct answer is option (a).

Note: one or the other plant growth regulator influences each period of development or advancement in plants. These jobs could be individualistic or synergistic; advancing or hindering. Also, beyond what one controller can follow up on some random life function in a plant. Elements like temperature and light influence plant development functions (vernalisation) by means of plant development controllers.