The correct option is D Ripening of fruits
Gibberellins are plant growth substances that promote bolting (the process of development of shoots prior to the reproductive phase) in beet, cabbage, and other plants with rosette habitat. They are used for the elongation of stem and to increase the internodal length in plants. They also mobilize food reserves in germinating seeds and are influential in fruit development. They help in the elongation and shape formation of fruits like grapes.
Ripening of fruits is an effect of ethylene.