Final answer:
The correct answer is Anchoring Heuristic.
Step-by-step explanation:
The correct answer is a) Anchoring Heuristic.
Anchoring heuristic refers to our tendency to rely on initial values or quantities when estimating the actual value or quantity of something. In this case, people give larger estimates of the length of the Mississippi River when asked if it is shorter or longer than 5000 miles vs 500 miles because the initial value provided acts as an anchor and influences their subsequent estimates.