The karez well system
a. was the first known use of wells
b. was a postindustrial system
c. transported groundwater from a distance
d. all of the above

The correct answer is c. transported groundwater from a distance

It wasn't the first known use of wells as wells older than them were found in places like Cyprus and Egypt and Austria who were as old as 6000-8000 years before common era. It also wasn't a postindustrial system as it was used in ancient china in the expansion of trading during the silk road trading era. It only leaves C as the correct answer.