A student investigates the requirements for photosynthesis using a plant with variegated leaves. A variegated leaf has a green center containing chlorophyll and a white margin lacking chlorophyll.
The student partially covers one healthy leaf with a strip of black paper, as shown in the diagram below.
The plant is left in bright sunlight for 24 hours24\text{ hours}24 hours. The leaf is then detached, decolourised in boiling ethanol, and tested for starch using iodine solution.
Which diagram correctly shows the distribution of starch in the leaf after the iodine test?
Leaf A
Leaf B
Leaf C
Leaf D