To calculate the adjusted amount of energy that is available to organisms that are one trophic level above producers, you would use:
Net primary productivity plus amount of organic material used in respiration.
This is because the energy available to primary consumers (the first trophic level above producers) is derived from the net primary productivity of the producers, which accounts for the energy that remains after respiration. Therefore, primary consumers utilize energy from the net primary productivity. However, the question is slightly ambiguous; the most relevant calculation involves considering the energy that is not lost to respiration, which directly involves net primary productivity.
More accurately, in ecological terms, the energy available to primary consumers is typically equated to the net primary productivity of producers, as this indicates the energy that is left after accounting for energy lost to respiration.
In summary, out of the choices provided, the best interpretation related to energy availability for the next trophic level would be:
Net primary productivity plus amount of organic material used in respiration.
Although this does not perfectly match the ecological energy transfer formula, it hints at understanding the energy flow through ecosystem trophic levels.