Four point charges are fixed at the corners of a square of side length \(2a\) centered at the origin in the \(xy\)-plane, with charges \(+q\) at \((a, a)\), \(-q\) at \((-a, a)\), \(+q\) at \((-a, -a)\), and \(-q\) at \((a, -a)\).

A small positive test charge \(+q_0\) is placed, one at a time, at four designated locations: the center \(O(0, 0)\), the edge midpoint \(A(a, 0)\), the edge midpoint \(B(0, a)\), and the exterior point \(C(2a, 0)\).

Which of the following correctly ranks the magnitude of the net electrostatic force \(F\) exerted on the test charge at each location?