In Autumn, Chlorophyll Is Degraded in the Leaves of Deciduous

In autumn, chlorophyll is degraded in the leaves of deciduous trees. Why do the leaves change colour to shades of yellow, orange or red?

A) Sugars from sap fill the leaves prior to winter.
B) Degraded chlorophyll changes into many other colours.
C) In the absence of photosynthesis, the leaves produce energy exclusively by aerobic cellular respiration.
D) Other pigments such as carotenoids are still present in the leaves.