Final answer:
With a constant and positive growth rate, the population size would statistically increase each year, representing exponential growth until it reaches the environment's carrying capacity.
Step-by-step explanation:
If the growth rate of a population is positive and remains constant, the number of people added to the population would increase each year. This scenario describes an exponential growth, in which the population size doubles at regular intervals, assuming there are no limits on resources or space. Even though in reality various factors such as resources and environmental resistance can alter this pattern, leading to logistic growth, the question assumes a constant positive growth rate. When a population reaches the carrying capacity of its environment, growth rates slow and level off, hence why option d is not relevant in this case.