Final answer:
After an interview, you should send a follow-up letter, typically a thank-you email, to make a good impression and reaffirm your interest and qualifications for the position.
Thus, the correct option is c.
Step-by-step explanation:
To help ensure that you make a good impression on a potential employer after an interview, you should send a follow-up letter. This is usually in the form of a thank-you email that you send within 24 hours after the interview.
The follow-up letter is your opportunity to reaffirm your interest in the position and to remind the employer of your qualifications and the good fit between your skills and the job requirements.
It is important to remember that while a strong cover letter and résumé are crucial to getting an interview, the follow-up after the interview also plays a significant role in the hiring process.
Therefore, the correct option is c. follow-up letter