An Experimenter Wants to Study the Effects of New and More

An experimenter wants to study the effects of new and more restrictive gun control laws on attitudes towards hunting. Six months prior to the enactment of the new legislation, a sample of citizens is interviewed with respect of attitudes about the appropriateness of allowing people to kill animals for sport and about the justification for allowing hunters to own powerful weapons. The same people are interviewed with respect to these same themes six months after enactment of the legislation. This research would seem to be an example of which of the following methods?

A) case study
B) control group post-test design
C) field experiment
D) closed questionnaire study
E) single group pre-test/post-test design