The correct option is D
Cladode is an aerial modification of the stem where the stem flattens and modifies into a leaf like structure. As flowers are normally present on the stem,here the flowers appear in the middle of the leaf like structures. Also, the true leaves are reduced to scale leaves. E.g. Leaf like structure in Ruscus.
Phylloclade is, also, an aerial modification of a stem where the stem is modified into a flat, fleshy and green leaf-like structure that carries out photosynthesis like a leaf. Also, here the leaves are modified into spines. The phylloclades consist of several nodes and internodes, whereas cladodes are usually one internode long. E.g. It is thick, fleshy and succulent in Opuntia.
When the stalk or the petiole of a leaf expands or flattens and performs photosynthesis, the modified petiole is known as phyllode. E.g. Australian Acacia.
Sucker is a sub-aerial modification of the stem. They are lateral non-green branches that originate from the basal underground portion of the main stem. It is also known as an underground runner. It grows horizontally below the soil and comes out obliquely upward giving rise to leafy shoots. Eg. Banana, pineapple. Banana plant