Which of the Following Options Lists the Events Leading to Leaf

Multiple Choice

Which of the following options lists the events leading to leaf fall in deciduous trees in the correct order?

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