In what is today the southwestern united states, which successful farming strategy did early native american groups use?

a. large permanent settlements
b. trade with mesoamericans
c. complex irrigation systems
d. giant earthwork mounds

I believe the answer is: c, Complex irrigation systems

The terrain where native american live on had a different height in elevations which make it really hard for them to obtain water for their agricultural field. And yet, the natives manage to develop Complex irrigation systems that allow them to allocate the water from the higher ground into the all the agricultural fields in different elevation.

i don't get what you mean

explanation: