A Research Worker Plans to Evaluate High School Students' Reactions

A research worker plans to evaluate high school students' reactions to a new policy on closed campus stations. He locates himself near the office of the dean, where he interviews every fourth student who visits the dean. He eventually secures data from 100 interviews and publishes his findings as the "Reactions of high school students to a new policy for a closed campus. What may be wrong with this approach?

A) Too small a sample
B) Inadequately defined problem
C) Inadequate techniques of analysis
D) Biased sample