An overestimated prediction about the probability of an event based on frequency of the event's past occurrences is known as:

An overestimated prediction of an event's probability based on how frequently it comes to mind is the availability heuristic.

It works by judging likelihood from the ease with which past instances are recalled.

Hindsight bias (option A) is the tendency to see an outcome as having been predictable after it has occurred.

The representativeness heuristic (option C) judges probability by how well a case matches a stereotype, not by frequency of recall.

Divergent thinking (option D) is generating many varied ideas, a feature of creativity, not a probability judgement.

The availability and representativeness heuristics were described by Amos Tversky and Daniel Kahneman.