"A. cutting down most of the trees in a forest to make furniture" is the correct answer because some trees play a vital role in processing the carbon in the air.
Anthropods have exoskeletons
We know, only 10% of energy transferred from each trophic level. Plant can capture 1% energy from the sun. According 10% law only 10% energy transfer to next level. Thus if plant has 1%- trophic level 2 will have 0.1%; then third trophic level will have 0.01% and we human if we are on fourth level then we will have 0.001%.
Thus correct answer is 0.001%.