Which of the Following Is Not a Factor Responsible for the Invalidation

Which of the following is not a factor responsible for the invalidation of test marketing study results?

A) Test market areas are representative of the market in general in terms of population characteristics, competition, and distribution outlets.
B) Sample size and design are incorrectly formulated because of budget constraints.
C) Pretest measurements of competitive brand sales are not made or are inaccurate.
D) Test stores do not give complete support to the study such that certain prices may not be held constant during the test period.