Question

why are there fewer top-level predators compared to primary consumers?
all top-level predators have specific prey to hunt.
top-level predators rarely add to the population.
there is less available energy at higher trophic levels.

Explanation:

In an ecosystem, energy transfer between trophic levels follows the 10% rule. Only about 10% of the energy from one level is passed to the next. Primary consumers (herbivores) get energy from producers (plants). Top - level predators (carnivores) are at a higher trophic level. Since there is less energy available at higher trophic levels (due to energy loss at each transfer), fewer top - level predators can be supported compared to primary consumers.

Answer:

C. There is less available energy at higher trophic levels.