Order the group of quadratic functions from the widest to the narrowest graph.
y = 2x^2 , y = 5x^2 , y = 1/3 x^2

a. y = 5x^2, y = 2x^2, y =1/3 x^2
b. y =1/3x^2, y = 2x^2, y = 5x^2
c. y = 1/3x2, y = 5x2, y = 2x^2
d. y = 2x^2, y =1/3x^2, y = 5x^2