Consider the Following to Answer the Question(s) Below

Consider the following to answer the question(s) below:
Management styles differ among organizations and may potentially affect employee job satisfaction. A sample of employees was randomly selected from each of three companies with different management styles (Authoritarian, Laissez-faire and Participative) and asked to rate their level of job satisfaction on a 10-point scale (10 being the highest level of satisfaction) . The data collected and partial ANOVA results appear below.

-Suppose that employees fall into several job categories, such as clerical, technical, or professional. Which of the following statements is true?

A) We are sure that job category is not a confounding variable.
B) Job category may be an outlier variable.
C) A randomized block design using job category as the blocking variable cannot improve the study.
D) Job category may be a confounding variable, and a randomized block design using job category as the blocking variable might improve the study.
E) Job category is not a lurking variable, and a randomized block design using job category as the blocking variable cannot improve the study.