The night nurse is preparing to pull night medications for a client. Levofloxacin is scheduled to be given at 0030. The nurse will give this medication at which time?

Number 4 is correct.

Medication times are given in military times, based on a 24-hour clock. Midnight is 2400 hours, at which time the clock resets to 0000. Medications due at 0030 are then due at 12:30 a.m. Using a 24-hour clock instead of a 12-hour clock eliminates the need to designate a.m. or p.m. for medication times.