Which of the following is the best definition of the representativeness heuristic?

People sometimes base their estimates on how "representative" an event is of its category rather than on true probabilities

People base their estimates of the frequency of an event on how easily the event comes to mind, with more easily$-$retrieved examples considered to be much more frequent

People use the first piece of information provided to them to make an estimate

People reject information that doesn't conform to their personal belief