The correct option is C Abscission
A layer of cambium like cells produced at the base of leaf or pedicel is known as an abscission layer. Abscission is the shedding of various parts of an organism. In plants, it is dropping of leaf, fruit, flower or seed. Plant will abscise a part either to discard a part that is no longer necessary, such as a leaf during autumn or a flower following fertilization or for the purposes of reproduction. If a leaf is damaged, a plant may also abscise it to conserve water or photosynthetic efficiency, depending on the plant as a whole. The abscission layer is a greenish-grayish color.
So, the correct answer is 'Abscission'