The correct option is B Photosynthesis
The primary function of a leaf is to perform photosynthesis.
When it takes functions other than photosynthesis, the leaf is said to be modified.
In onion, leaves store food and get fleshy.
In insectivorous plants, leaves are modified to trap insects.
In Bryophyllum, vegetative buds develop on the margin of leaves that can develop into new plants.