How much energy is transferred from one trophic level to next trophic level?

The correct option is A. 10%.

Lindemann's 10% Law:

1. This law states the organisms in a particular trophic level have 10% of the energy available to them from the previous trophic level. ​
2. As an example, the deer forms the primary consumer in the ecosystem while the lion is the secondary consumer forming the next trophic level of the food chain.
   
3. If the energy present in deer is 200J then the energy transferred to lion is 10% of the total energy which will be 20J.