Answer:
A. Difficulties in overland travel encouraged trade with Asia and Canada.
Explanation:
Before the country was able to fully expand all the way to the West, people in the West coast were quite separate from those on the East one. This is because most of the population lived in the East, and this was where most markets and customers were located. Travelling from East to West was extremely difficult, and this made trade difficult. Therefore, during those years, Washington traded mostly with Asia and Canada.
