Spot the Internal Validity Threat that is MOST likely at work for each of the following scenario: After viewing the theft and speaking with the experimenter as well as campus security, all participants were asked to return on day two to discuss what they saw more formally with the police detective. Unfortunately, a hurricane hit the next day and closed down campus for two weeks, so participants were unable to return as quickly as the researchers would have liked. Still, the interviews commenced three weeks after the theft, and researchers found that those in the experimental group did not differ in their memories regarding the presence of a gun compared to those in the control condition. That is, the mean score that a gun was present was similar for the experimental group (M = 65%, SD = 11.4%) and the control group (M = 63%, SD = 13.26%).

a. Maturation
b. Regression to the mean
c. Selection
d. Mortality
e. Instrumentation
f. Testing
g. History
h. Interactions
i. Diffusion
j. No Threat