Correct option is C. Higher trophic levels tend to be less discrete than the lower ones.
The relative loss of energy increases in
successive trophic levels. Primary consumers use
10% of the energy stored in plants. Secondary and
tertiary consumers transfer 20% of the energy from
their own bodies so they are more efficient. In going
from lower to higher trophic levels energy transfers
are insufficient so making the food chains limited
to only 4-5 trophic levels. Higher trophic levels are
less discrete due to their less specialised food habits.