What Best Explains This Observation: Consumers Directly Use Approximately 20

What best explains this observation: consumers directly use approximately 20 percent of a forest's net primary productivity (NPP) while decomposers directly use approximately 80?

A) Decomposers are more efficient at obtaining energy than consumers.
B) Forest ecosystems do not have a very high NPP, so they cannot support as many consumers as other ecosystems can.
C) Consumers eat only certain parts of organisms, such as fruits or muscle tissue, while decomposers obtain energy from the entire body of the food organism.
D) Secondary consumers eat the primary consumers more quickly than the primary consumers can eat the producers, thus leaving most of the NPP available to the decomposers.