Find a first-order ordinary differential equation (ODE) in the form (f(x,y,y') = 0) whose general solution is given by the family of parabolas (y = cx²).
a) (y' - 2cx = 0)
b) (y' + 2cx = 0)
c) (y' - cx² = 0)
d) (y' + cx² = 0)