(E) is wrong/unsupported because we don't know that Noguchi helped Brancusi to
produce sculptures. According to lines 17-20, Noguchi cut and polished stone and polished the brass and bronze sculptures. All in all, Noguchi was doing the side work. It would be a stretch to infer that Noguchi was actually helping to produce Brancusi's works (Brancusi "never took students").
An analogous case (exaggerated for emphasis) would be a janitor at Apple's HQ claiming that by dusting the prototypes in the super-secret room, he or she helped in producing the iphone 5....