Question

for how long did the pony express operate?
1 year
20 years
10 years

Explanation:

The Pony Express operated from April 3, 1860, to October 26, 1861, which is approximately 1 year. The other options (20 years, 10 years) are incorrect as historical records show its short - lived operation of about a year.

Answer:

1 year (the option with "1 year")