Answer: A. There were steep cliffs and a raging river to cross.
Explanation: The Columbia River was frequently used to transport people and their belongings in canoes or on rafts, but sometimes raging rapids and dangerous currents from flooding caused the vessels to tip and people drowned.
There were steep cliffs near the Willamette Valley and people would have to walk the steep, hazardous trail over the Lolo Pass or later, the somewhat easier Barlow Road.