Final answer:
Dave is effective but not efficient due to his high quality rating and slow working speed. Option c is correct..
Step-by-step explanation:
Dave, who has the highest quality rating but is the slowest worker, can be characterized as effective but not efficient. Efficiency refers to the ability to accomplish a task with minimum wasted resources, such as time or cost. In this case, Dave's slow working speed leads to higher labor costs per unit, making him less efficient. However, his high quality performance indicates that he is effective in producing work of superior quality.
Dave has the highest quality rating in the department, which makes him effective because he meets the desired standards of quality. However, efficiency refers to the ability to accomplish a job with a minimum expenditure of time and effort. Since Dave is the slowest worker and his labour cost per unit is the highest, it is clear that he is not efficient. Therefore, the correct answer to the question is that Dave is effective but not efficient.