What effect did the radio have on rural North Dakota during a time when the Nonpartisan League (NPL) and the Independent Voters Association (IVA) were influential?
A) Limited impact as radio penetration was low in rural areas.
B) Strengthened isolation in rural communities due to lack of access.
C) Enhanced communication, education, and political awareness among rural residents.
D) Induced political polarization, leading to increased tensions between NPL and IVA supporters.