C is the only one that makes sense. Since there's a game, there are a lot of people going to/coming back from the stadium, and thus the traffic gets heavier.
The other options make no sense, in terms of cause-effect, and they only look like coincidences.
Y=3x-4 This affects the previous line because now the slope is a positive which completely turns it around. and the Y intercept is now on the opposite side of the X axis