The correct answer is B) As a way to transport goods and people.
Rivers were important to people migrating west "As a way to transport goods and people."
With the Westward expansion, the American people started to settle in the western portion of the territory. Rivers played a major role in the exánsion because they served As a way to transport goods and people.
Let's have in mind that US President Thomas Jefferson had ordered the purchase of the Louisiana Territory owned by the French. So in 1803, after the purchase, Thomas Jefferson ordered the Lewis & Clark expedition to explore the western territories. The Expedition lasted 3 years. After that time President Jefferson was briefed about the findings and that is when he authorized the westward expansion.