Which of These Is the Best Example of Acclimatization to Light

Which of these is the best example of acclimatization to light variation that is accomplished by morphological, rather than physiological means?

A) Plants in different climates have different forms of the same photosynthetic enzymes, according to which form operates best in the plant's particular environment.
B) Spearscale plants grown in different light environments vary in maximum net photosynthesis rate, nighttime respiration values, and light compensation points.
C) Unlike other plants, lichens in the Arctic can photosynthesize at temperatures close to freezing.
D) Golden banner plants adapt to varying light conditions by adjusting their number of chloroplasts and the thickness of their leaves.