Answer: C. They designed water systems.
Step-by-step explanation:
Engineering may seem like a recent thing but in fact has been around for millennia and contributed significantly to helping humans conquer as much of the environment as we could in order to survive.
This passage describes one of the earliest contributions to society brought by engineering by showing how engineers were needed to build a system that would reduce flooding and direct water to where it was needed as well as to repair that system.