The correct option is B Gaseous exchange
Lenticels are lens shaped opening formed in bark due to secondary growth. They permit gaseous exchange in woody trees.
Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere.
Phloem transports food from the leaves to the rest of the plant.
Photosynthesis is the process by which plants, some bacteria, and some protistans use the energy from sunlight to produce sugar. In plants this process takes place in the leaves.