Quadratic functions r and s are graphed on the same coordinate grid. The vertex of graph r is 2 units to the left of the vertex of the graph of s. Which pair of functions could be used to create the graphs of r and s?
a.r(x)=(x+2)^2
s(x)=x^2
b.r(x)=x^2-2
s(x)=x^2
c.(x)=x^2+2
s(x)=x^2
d.(x)=(x-2)^2
s(x)=x^2