The correct option is B Xerophytes
A sunken stomata is stomata in a small pit, which prevents water loss through transpiration. Sunken stomata are commonly found in Xerophytes, that are plants adapted to grow in desert conditions. Hydrophytes are plants that grow in water. Mesophytes are terrestrial plants which are adapted to neither a particularly dry nor particularly wet environment. Halophytes are plants that grow in highly salinity.