What is the combination of resources used and conditions tolerated in the absence of competitors called?

The combination of resources used and the conditions tolerated in the absence of competitors is called FUNDAMENTAL NICHE.

The niche of an organism refers to the manners with which it interacts with its environment; it encompasses the roles that the organism performs within its localized ecosystem. These roles are usually affected by the quantity of needed resources available and the presence or absence of competitors.  

There are two types of niche, fundamental and realized niche. The fundamental niche refers to the complete environmental conditions that a population of specie can occupy and utilize, if no limiting factor exists. This niche is very efficient in term of resources use due to the absence of intraspecific competition, predation and environmental stressors.  The fundamental niche is a potential niche that could be filled by living organisms.  

it is either c or d and i know for sure it is not a or b