Plant hormone controlling fruit ripening is
A.IAA
B.GA
C.Ethylene
D.Kinetin

Hint: IAA (Indole Acetic acid), GA (Gibberllic acid), Ethylene and Kinetin all are the phytohormones. Phytohormones are also called plant hormones. Plant hormones are the signal molecules that occur in extremely low concentrations. Plant hormones are the hormones that are responsible for the plant growth and plant development, pathogen defense, stress tolerance, etc. They are the small organic molecules.

Complete answer:
A.IAA (Indole Acetic acid):
1.Indole acetic acid is a plant hormone that belongs to the class of auxins.
2.Indole acetic acid is a derivative of indole.
3.It is colourless solid which is soluble in the polar organic solvents.
4.Indole acetic acid has many effects such as cell elongation and cell divisions.
5.This hormone acts as a signaling molecule for the development of the plant organs and coordination of the growth.

B.GA (Gibberllic acid):
1.Gibberellic acid is also called as the gibberellin A3, GA and GA3.
2.When gibberellic acid is purified, it is a white to pale yellow solid.
3.Gibberellic acid is a pentacyclic diterpene acid. Gibberellic acid promotes the growth and elongation of the plant cells.
4.Gibberellic acid also acts as a stimulant for rapid stem and root growth, it induces mitotic division in the leaves of some plants and increases seed germination rates.
5.Gibberellic acid is also used in laboratories in order to trigger germination in seeds.

C.Ethylene:
1.Ethylene is a first identified plant hormone.
2.Ethylene is an unsaturated carbon compound which acts as a plant hormone in its natural form.
3.It is a multifunctional hormone regulating both growth and senescence.
4.The functions of the Ethylene include stimulating the fruit ripening, Increases the speed of leaf and flower senescence, Induces flowering, Inhibits stem growth, Induces root growth in order to absorb more and more water, Helps in determining the sex of a flower, Helps in root initiation and pollination.

D.Kinetin:
1.Kinetin is a type of cytokinin that promotes cell division or cytokinesis.
2.Kinetin was first isolated by Miller and Skoog et al.
3.This hormone was given the name kinetin because of its ability to induce cell division.
4.The Kinetin was shown to naturally exist in the DNA of organisms including humans. Kinetin is used in tissue culture. It is also used in cosmetic products as an anti ageing agent.

Hence the correct answer is OPTION(C)

Note: Ethylene is an organic compound which is also used in manufacturing numerous products such as plastics, paints, rubber, toys, detergents, etc. It is also used in agricultural work for obtaining more yield.