Answer: c) availability of employment opportunity
Step-by-step explanation:
According to Karl Marx theory which describes that employment opportunity plays a major role in population growth.Increment in population is impacted through capitalist system .Reduction in incentives and wages or low employment chances tend to increase the fertility rate according to the theory and thus population tends to increase.
Other options are incorrect because food supply , family structure and resource requirement does not act a a factor for determining population growth as per Karl Marx theory. Thus, the correct option is option(c).