Answer: b. resource heterogeneity
Explanation: Resource heterogeneity could be explained as the variation or difference in resources possessed by firms operating in the same market. These differences or diversity of resources plays a huge role in giving one firm the competitive edge over the other. In the scenario described above, True Ion Inc's innovative capability provided by it's resource-base due to human and capital investment gives it the competitive edge over other market competitors such as Electron Inc. whose resource-base lags in the aspect of innovation.