The correct answer is option 1, Greenwich. The Prime Meridian is an imaginary line that divides the Earth into the Eastern and Western Hemisphere, representing 0° longitude. It runs through the Royal Observatory in Greenwich, London, UK.

Option 2, Ujjain, is incorrect. Ujjain is a city in India but it is not located on the Prime Meridian.

Option 3, New York, is also incorrect. New York is a city in the United States, but it is located at a longitude of around 74°W, which is far from the Prime Meridian.

Option 4, Tokyo, is also incorrect. Tokyo is the capital city of Japan, but it is located at a longitude of around 139°E, which is on the other side of the Prime Meridian.

So, the Prime Meridian passes through Greenwich, London, making option 1 the correct answer.