The correct option is A Delay senescence
Gibberellins delay senescence and the fruits can be left on the tree longer so as to extend the market period.
Ethylene promotes senescence and abscission of plant organs especially of leaves and flowers. Ethylene is highly effective in fruit ripening. They breaks seed and bud dormancy, initiate flowering and for synchronizing fruit-set in pineapples.
So, the correct answer is "option C"