Final answer:
The international time 1800 corresponds to 6:00 PM in the 12-hour regular time format.
Step-by-step explanation:
To convert 1800 international time to the 12-hour regular time, we need to determine the corresponding time in either AM or PM format. International time uses a 24-hour clock, where 1800 represents 6:00 PM. Since we want the 12-hour format, we convert 6:00 PM to AM/PM format, which remains the same. Therefore, the answer is option B: 6:00 pm.