Final answer:
To convert standard PM times to military time, add 12 to the hour of the post-meridian time.
Step-by-step explanation:
To figure out military times after 12:00 noon, you need to add the number of the hour in the post-meridian time to the number 12. Therefore, the correct answer to the question is a) 12. For example, if the post-meridian (p.m.) time is 3:00 p.m., in military time this would be 15:00 hours. This is because 3 (the hour) + 12 equals 15. Similarly, for 9:00 p.m., you would add 9 to 12, which equals 21, so in military time it would be 21:00 hours.