Final answer:
Encourage candidates to update their knowledge, skills, and abilities to engage passive candidates in the applicant pool.
Step-by-step explanation:
Utilizing an Applicant Tracking Database to Engage Passive Candidates
The best way to utilize an applicant tracking database to engage passive candidates in the applicant pool is to encourage candidates to update their knowledge, skills, and abilities (option D).
Passive candidates are those who are not actively seeking new job opportunities but may be open to considering them if the right opportunity comes along.
By encouraging candidates to update their knowledge, skills, and abilities, you are increasing their chances of being a good fit for future job openings and increasing their engagement with the applicant tracking database.