In an Experiment, Participants Were Told of a Previously Unknown

In an experiment, participants were told of a previously unknown tribe living on a Pacific island. Only one member of this tribe had been observed so far and was found to be obese. When asked how likely it was that all members of the tribe were obese, participants were unwilling to extrapolate this information. This shows that participants:

A) were using the representative heuristic
B) had prior beliefs about these islanders
C) are sometimes sensitive to the sample size and can take this into account when making a judgment
D) are unwilling to make a judgment as they are wary of making an error