Business Consultant: Our analysis of managerial effectiveness reveals that the skill sets of managers play a vital role in the success of the organization. It is especially important that the skills that entry-level managers have match those required to actually perform their job. Every entry-level manager who received an unsatisfactory rating was found to lack some of these required skills. Since the entry-level positions in this organization require technical skills, I recommend that the selection process for entry-level managers focus on ensuring that candidates have the technical skills required for entry-level positions. If all of the business consultant's statements are true, which of the following must also be true?

a. Every entry-level manager who received at least a satisfactory rating had the required technical skills.
b. All the entry-level managers who lacked the required skills received an unsatisfactory rating.
c. The most successful managers had the greatest technical skills.
d. The only possible ratings for entry-level managers are "satisfactory" and "unsatisfactory."
e. All managers who had the required technical skills did not receive an unsatisfactory rating.