Texas Certified Nursing Assistant (CNA) Practice Exam 2025 - Free CNA Practice Questions and Study Guide

To convert standard time to military time, you need to understand how the military uses a 24-hour clock. Military time runs from 0000 hours at midnight to 2359 hours just before midnight.

For the given time of 9:00 p.m., you start at 12:00 a.m. (midnight) and count the hours up to the evening. In military time, you add 12 to any hour after noon. Therefore, for 9:00 p.m., you take 9 and add 12, resulting in 21:00 hours.

Consequently, 9:00 p.m. in military time is correctly expressed as 2100 hours. This is why this answer is the appropriate conversion.