Narrative 7-1 Unverferth Manufacturing Is a Manufacturer and Supplier of Innovative Agricultural

Narrative 7-1
Unverferth Manufacturing is a manufacturer and supplier of innovative agricultural equipment. Recently it began developing a new 12-row strip-till subsoiler that is ideal for cotton production. Before introducing the new tiller to the market, Unverferth developed and tested nearly three dozen product prototypes.
-Refer to the Narrative 7-1.What did Unverferth use to produce the best possible tiller before introducing it to the market?

A) service development
B) process duplication
C) design iteration
D) design compliance