On the window sill

These leaves have got clear burnings. This surprises Petra. They belong to potted plants on her window sill in the bath room. The window pane consists of irregularly formed glass. Petra thought, that plants were protected in the house, actually.

Can you explain to Petra what must have happened, that has damaged her plants?

a) While passing through a pane of glass, sunlight is always intensified. Thin areas of the leaves are not protected from the heat and will be damaged.

b) The sunlight is refracted in the irregularities of the window pane and is collected on smaller areas of the leaves. The leaves are hit by too much sunlight and so they are ruined.

c) The ceiling lamp in the room does not shine uniformly. The areas on the leaves which only get less light will get damages.

d) Sunlight cannot pass through the wide parts of the window pane. Areas of the leaves which are always in the shaded places, die.