One problem with using archival data (e.g., existing records of disturbances) to demonstrate that exposure to uncomfortable levels of heat causes people to behave aggressively is that

a. it is difficult to access such records.
b. by definition, people who participate in disturbances are not a random sample.
c. more people might simply be outside on a warm day than on a cold day.
d. such disturbances do not involve the kind of aggression of interest to social psychologists.

Answer: C