Answer:
Fischer projection is the method used for representing a three-dimensional organic molecule as a two dimensional molecule.
This method can be used for determining the D- and L- configuration of the organic molecules.
In the Fisher projection of carbohydrate molecule, if the hydroxyl group attached to the last stereocenter of the molecule is placed on the right-hand side, then the carbohydrate is said to have D-configuration.
Whereas, if the hydroxyl group attached to the last stereocenter of the molecule is placed on the left-hand side, then the carbohydrate is said to have L-configuration.