Karl —, German designer who built the first car to be driven by an internal-combustion engine (4)

(Other definitions for benz that I've seen before include "German engineer, builder of first car with internal combustion engine" , "German engineer who built the first petrol-engined car" , "Motor man" , "German engineer, first to build a patented car, d. 1929" , "German pioneer of the internal-combustion engine, associated with Mercedes" .)