What Advantage Would There Be for an Ecosystem Ecologist to Measure

Multiple Choice

What advantage would there be for an ecosystem ecologist to measure net ecosystem production (NEP) instead of net primary production (NPP) ?

A) NPP cannot be expressed in energy/unit of area/unit of time.
B) NEP can be expressed in terms of carbon fixed by photosynthesis for an entire ecosystem, minus respiration by producers, allowing the measurement of net CO₂ flux.
C) NEP represents the amount of energy from light converted to chemical energy, minus the energy used by all organisms for cellular respiration, which could indicate whether or not carbon is being stored.
D) NPP shows the rate at which the standing crop is utilized by consumers.