A trans-continental railway is one that spans an entire continent. The railway between San Francisco (West Coast) and New York (East Coast) in the United States is a classic example of a trans-continental railway line.
Option A: Yokohama and Vancouver are in different continents and separated by the Pacific Ocean — not connected by rail.
Option B: Auckland and Honolulu are also on separate islands, making rail connection impossible.
Option C: Correct — San Francisco and New York are connected by one of the world's earliest and most famous trans-continental railways.
Option D: London and Aden are not on the same continent and have no rail connection.
So, the correct answer is (C): Between San Francisco and New York.