Final answer:
The best example of the availability heuristic is assuming a business person is ruthless based on a few previous encounters, as it exemplifies the bias of relying on easily recalled events to make judgments.
Step-by-step explanation:
The availability heuristic is a cognitive bias where people make judgments based on the most easily recalled examples, often leading to an overestimation of the likelihood of certain events. Among the provided options, the best example of the availability heuristic is 3) Assuming that a business person is ruthless because the last three you have met were not nice people. This demonstrates the availability heuristic because the judgment is based on a small sample of easily remembered encounters rather than a broad and statistically sound dataset.