Mountain Men young American trappers and traders in the Rocky Mountains.
Option(b);
<u>Explanation:</u>
Mountain men were a group of explorers who discovered the new immigrant trails that led to new territories.
These inventionsresult in the motivation for trade and other commerce opportunities.
They improved roads that allowed free movement of wagons that enables the Americans to settle in the West.
Also, they organized wagons to facilitate easy transportation.
Their main source of trade was fur which initially gave rise to their trade operation and functions that introduced new dealings lasted for nearly three decades.
