In the Prairie Community Studies by Tilman and Colleagues,two Hypotheses

In the prairie community studies by Tilman and colleagues,two hypotheses were proposed to explain the increase in NPP as species richness increased.One involved accidental sampling,in which samples by chance included one or more "superspecies" that had a disproportionate effect on community function.Which other explanation did Tilman and his colleagues decide was more reasonable?

A) Niche complementarity,leading to more efficient resource use
B) Niche complementarity,leading to increased reproductive rates
C) Changes in microclimate,leading to increased reproductive rates
D) Decreased species evenness,leading to a few species influencing community function
E) Increased species evenness,leading to all species equally influencing community function