B.
Its a Paradox question;
Trains are suited for connecting all areas but winter sports tourism.
Aim :- Look for an option which shows negative about train in winter regions.
A Commuter trains do not need to negotiate traffic in the way that buses and cars do.
No clarification in paradox about trains in winter sports tourism.
B Building a railway is much more expensive than other forms of transport in mountainous terrain.
Yes, Hang on.
C In order to minimize damage, trains must be periodically serviced, which can be an expensive process.
So what ? a generalized statement.
D In some areas, trains are used to transport dangerous chemicals and industrial supplies.
Some ? Not related to winter sports tourism. Kick this option out
E Trains in areas that rely on winter sports tourism have approximately the same safety record as those that run anywhere else.
Does not co relate the Paradox.
So, B is the best of five available options.