Which part of a green plant would lose the most chloroplasts as a summer turns fall?

The leaves, because they're actually the part that has chloroplasts, therefore, the parts of the plant that'll change colour the most.

Hope it helped,

BioTeacher101

Leaves

Explanation:

The leaves of a tree/plant consists of chloroplast. Hence, if summer turns fall it is the leaves that would lose most chloroplast. Chloroplast consists of chlorophyll that is useful in the process of photosynthesis.  

Not only this during fall season the leaves even fall from the branches of the tree. Hence, for any green plant loss of chloroplast occurs mainly in the leaves and in a large amount

the correct option is option d