John conduct photosynthesis experiment, he use lugol, alkohol and other. he use two samples of leaves. one leaf covering by alumunium foil, and other not covering by alumunium foil. what is the function of lugol?
A.
Killing the pathogen (virus, bacteria, and other microorganism)

B.
Testing amylum in leaf

C.
Loosing chlorophyll in leaf

D.
Increase photosynthesis rate​