Among those automobile mechanics who own their own garages and completed a qualifying course at Main Street Technical School, 35% earn above $80,000 a year. Among those who own their own garages but did not complete the qualifying course at Main Street Technical School, only 10% earn above $80,000 a year. These figures indicate the importance of technical education in getting a higher salary.

The argument above depends on which of the following assumptions about the people mentioned in the statistics?

• AAt least one-third of the group of people who did not complete the qualifying course would today be earning more than $80,000 a year if they had completed the course.  
• BThe group of people who did not complete the qualifying course and the group who did are comparable in terms of factors that determine how much people are paid.  
• CMost of those people who did not complete the course did so entirely because of the cost of the course.  
• DAs a group, those persons who completed the course are more competent as mechanics than the group that did not.  
• EThe group of people who did not complete the qualifying course and who today earn more than $80,000 a year are more capable than the group that completed the course.