What is ethylene gas used for?

Which of the following is used to artificially ripen banana fruits?

Which hormone causes stunted growth in pea?

The Plant Growth Regulator $(PGR)$,ethylene,comes under the category of:

$I.$ More female flowers in cucumber
$II.$ $\alpha$-amylase production in barley grain
$III.$ Acceleration of fruit ripening in tomato
$IV.$ Delay in sprouting in potato tubers
From the given effects,identify the effects of ethylene and choose the correct option accordingly.

What is the influence of ethylene on plants?