262. During the early years of European settlement on a continent that was viewed as “wilderness” by the newcomers, Native Americans, intimately knowing the ecology of the land, were a help in the rescuing of many Pilgrims and pioneers from hardship, or even death. (A) Native Americans, intimately knowing the ecology of the land, were a help in the rescuing of (B) Native Americans knew the ecology and the land intimately and this enabled them to help in the rescue of (C) Native Americans, with their intimate knowledge of the ecology of the land, helped to rescue (D) having intimate knowledge of the ecology of the land, Native Americans helped the rescue of (E) knowing intimately the ecology of the land, Native Americans helped to rescue
I think that the so-called aswer C has big problem with the idiom "help sb do sth"? what do u think, guys?