Which of the following is/are true of world time zones? I. The world is divided into thirty time zones II. All time zones of the world are described in term of the number of hours difference between the standard meridian of that zone and the Greenwich Meridian III. All countries have more than one time zone IV. The time for all places east of Greenwich is designated slow, and time for all places left of Greenwich is designated fast

Answer: Option D

All time zones of the world are described in term of the number of hours difference between the standard meridian of that zone and the Greenwich Meridian. Each of Earth's 24 zones is one hour earlier then the one east of it, which equates to about 15° longitude for each. Although this is the general rule, there's not always a one hour difference between each time zone. Some countries have adopted a non-standard time, which may include a 30 or 45 minute offset.