Answer:
b. resource partitioning
Step-by-step explanation:
Resource partitioning, in biology, refers to the use of limited resources by similar species in different ways in order to reduce competition in an environment in which both populations of the similar species inhabit together. Similar specifies tend to rely on the same resources for survival. When similar species dwell in the same environment, to avoid extinction of one species as a result of intraspecific competition, one tends to use resources which are slightly different from the resources the other one rely on. This resource partitioning behavior is what is observed in the vole species.