Answer:
The correct option is 1000 units of energy.
Step-by-step explanation:
Most of the energy at each trophic level gets lost in the form of heat. Only a little amount of energy passes from one trophic level to the other. Scientists conclude that only about 10% of energy passes from one trophic level to another.
Hence, the flowers having 100,000 units of energy will pass 10,000 units of energy to the butterflies. The butterflies will pass 1000 units of energy to the birds.