The correct option is B Phylloclade is the modification of entire stem but cladode is the modification of only single internode of stem
Phylloclade is a specialized photosynthetic stem present in most of the xerophytes. In most of the xerophytes, leaves get modified into spines to reduce the rate of transpiration. Hence the stem becomes green to perform photosynthesis. Phylloclades have distinct nodes and internodes. Hence, phylloclade has several nodes and internodes. Phylloclade is found in Opuntia, Casuarina.
Cladode is also modification of stem and here only branches get modified to perform photosynthesis. Cladode is usually one internode in length. Cladode is found in Asparagus.