Which List Correctly Orders the Events Leading to Leaf Fall

Multiple Choice

Which list correctly orders the events leading to leaf fall in deciduous trees?

A) formation of abscission layer, increase in ethylene levels, decrease in auxin levels
B) shortening days, increase in ethylene production, formation of abscission layer
C) shortening days, formation of abscission layer, decrease in ethylene levels
D) decrease in ethylene levels, shortening days, formation of abscission layer