Which of the following describes how features of countries in north america influence change in these countries ?

Question

A.Most have flat terrain, making railroads the least expensive method of transporting goods. B.with oceans on both sides, most countries have access to many sea ports and trade routes. C. severe temperatures prevent trade between Canada and other countries most of the year. D.physical barriers such as rivers and lakes at their borders make trade difficult.
Id say D ?

Answer 1

Well, from Halifax to San Diego, North America abounds in seaports on the Atlantic and Pacific although Mexico has relatively small ones.

Answer 2

So the answer would be B?

Answer 3

That would be my answer, but you could disagree if you say why :)
I see oceans at the borders, not rivers or lakes for the most part (except the Rio Grande and some Great Lakes of course)

Answer 4

By the way, cost on a ship for freight is much less per mile than by any other method.