Answer:
Graph #2 for sure, both axis are linear and the curve is a parabola all right.
On graph #1: I can't for the life of me read the units on the Y axis, so you have to check: if they're going 2000 4000 6000, then that is a parabola as wel. If they're increasing esponentially, ie 2000 4000 8000, then one of the two axis is logarithmical and the curve is no longer quadratic.
