Answer:
Based on the context, the word "feasibility" means Achievability.
Explanation:
This excerpt is taken from "The story of the Pony Express" by Glenn D. Bradley.
This book tells how the United States was growing and telling the story of young people who had to cross difficult roads but were always very brave.
When we talk about the feasibility of something, we are saying how likely it is to do that. In other words we would be saying "proved how achievable was a transcontinental road ...
