The correct option is A Waxy cuticle
Stomata are small pores found in the leaves of the plant that helps in the gaseous exchange during photosynthesis and respiration. Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata. Chloroplast main role is to conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight. The primary function of the leafs waxy cuticle is to reduce water loss through the leaves, which is particularly important in arid deserts with little rainfall or Mediterranean climates with seasonal rainfall. So, option A is correct.