Stanley Was Surprised to Hear That Jennifer Had Been Treated

Stanley was surprised to hear that Jennifer had been treated by a psychiatrist ten years ago. When he first met Jennifer she seemed to be calm and rational, and she certainly didn't look "psychotic." If you were to ask Stanley to estimate the overall prevalence of psychological disorders, you should predict that

A) the representativeness heuristic would cause him to overestimate the overall prevalence rate.
B) the conjunction fallacy would cause him to overestimate the overall prevalence rate.
C) the availability heuristic would cause him to underestimate the overall prevalence rate.
D) the representativeness heuristic would cause him to underestimate the overall prevalence rate.