The Big Trunk Route refers to a major shipping route that connects various regions of the world. Among the given options, the correct answer is option 'B', which states that the Big Trunk Route runs through the North Atlantic Ocean. Let's explore the reasons behind this answer in detail:

The Big Trunk Route:
- The Big Trunk Route is a term used to describe a shipping route that is crucial for international trade and transportation. It is often referred to as a major artery of global maritime traffic.
- This route is utilized by numerous shipping vessels to transport goods, raw materials, and resources across different continents and regions, facilitating global trade.

The North Atlantic Ocean:
- The North Atlantic Ocean is the second-largest ocean in the world, bordered by Europe and Africa to the east and North America and South America to the west.
- It is a vital water body for maritime transportation, connecting major ports and trading hubs on both sides of the Atlantic.
- The North Atlantic Ocean serves as a key component of the Big Trunk Route due to its strategic location and the high volume of traffic it handles.
- Major ports along the North Atlantic include New York, London, Rotterdam, Hamburg, and Halifax, among others.
- These ports act as important hubs for trade between North America, Europe, and other regions, making the North Atlantic Ocean a crucial part of the Big Trunk Route.

Other Options:
- Option 'A', which mentions the Mediterranean Indian Ocean, is incorrect because the Mediterranean Sea and the Indian Ocean are separate bodies of water located in different regions.
- Option 'C', the South Atlantic Ocean, is also incorrect because it is located in the southern hemisphere and is not a part of the Big Trunk Route.
- Option 'D', the North Pacific Ocean, is also incorrect because although it is another major ocean, it is not specifically mentioned as part of the Big Trunk Route.

In conclusion, the Big Trunk Route runs through the North Atlantic Ocean due to its strategic location and the presence of major ports and trading hubs along its shores.