Final answer:
The correct answer is availability heuristic. People may think there are more mentally ill homeless people than there actually are due to the tendency to evaluate new information based on easily recalled examples.
Step-by-step explanation:
The correct answer to the question is a) availability heuristic.
The availability heuristic refers to the tendency to evaluate new information based on the most recent or most easily recalled examples. In this case, it means that people might think there are more mentally ill homeless people than there actually are because they can easily recall instances or stories of mentally ill homeless individuals, even though statistically they might not represent the majority.
For example, the media often highlights cases of mentally ill homeless individuals, making them more available for retrieval from memory and leading people to overestimate the prevalence of mental illness among the homeless population.