Explanation:

Diligent is an adjective that describes someone who is hard-working, persevering, and dedicated to their work or tasks. It is an important quality that is highly valued in the workplace, as it shows an individual's commitment towards their responsibilities. Let's discuss why option 'D' is the correct answer:

Hard-working:

Diligence is synonymous with hard work, which is the ability to put in consistent effort over a long period of time. It requires self-discipline, focus, and the willingness to push through obstacles to achieve goals. A diligent person is someone who puts in the necessary work to complete a task or project, regardless of how difficult or time-consuming it may be.

Progressive, Brilliant, and Inventive:

While these adjectives are also positive traits, they do not accurately describe someone who is diligent. A progressive person is someone who is forward-thinking and advocates for change, whereas a brilliant person is someone who is exceptionally intelligent or talented. An inventive person is someone who is creative and comes up with new ideas. While these qualities are admirable in their own right, they do not necessarily indicate a strong work ethic or commitment to completing tasks.

Conclusion:

In conclusion, the correct answer to this question is option 'D' - Hard-working. Diligent is an important quality that is highly valued in the workplace, as it shows an individual's commitment towards their responsibilities. Being hard-working is an essential component of diligence, as it requires self-discipline, focus, and the willingness to put in consistent effort over a long period of time.