Thomas Malthus is best known for his theory regarding population growth and its relationship to resources, particularly food supply. He argued that while populations tend to grow exponentially, food supply grows arithmetically, which would lead to a situation where the population would eventually outstrip the available food resources, resulting in famine, disease, and other factors that would limit population growth.
The correct answer to what Thomas Malthus argued is:
c. an ever-increasing population is constrained only by the food supply, resulting in chronic famines.