The correct option is B Symplast
The continuous cytoplasmic system running through the sieve tubes is called as symplast. The symplast of a plant is the inner side of the plasma membrane in which water can freely diffuse. The plasmodesmata allow the direct flow of small molecules such as sugars, amino acids and ions between cells. This allows direct cytoplasm-to-cytoplasm flow of water and other nutrients along concentration gradients. In particular, it is used in the root systems to bring in nutrients from soil. It moves these solutes from epidermis cells through the cortex into the endodermis and eventually the pericycle, where it can be moved into the xylem for long distance transport.
Thus, the correct answer is option A.