Which of These Is an Example of Gerrymandering

Which of these is an example of gerrymandering?

A) Districts are drawn to cover the same amount of geographic area, even if this means that population varies between districts.
B) A state designs districts to ensure that new candidates and incumbents have an equal chance at winning the election.
C) A district is drawn to be 95 percent Republican so that neighboring districts are more difficult for the Republican Party to win.
D) A Republican-leaning urban area is split up into multiple districts and combined with suburban areas that are majority Republican.