Answer : Option B) Assigning the decomposers and Detritivores to a particular trophic level.
Explanation : An energy pyramid’s is mainly used to show how the amount of useful energy which enters each level through chemical energy in the form of food decreases, as it is used by the organisms in every level.
The first level is assigned to producers, then comes primary consumers, secondary consumers and lastly tertiary consumers. It does not helps in assigning the energy for a group of decomposers.