Answer:
D. There is less available energy in the fourth trophic level because of the loss of energy through metabolism in each of the lower trophic levels.
Explanation:
Each successive trophic level contains about ten percent of the available energy from the previous trophic level. The other ninety percent is lost as heat to the atmosphere through metabolism by the organisms in that level. Therefore, there will be much less energy in the fourth trophic level.