suppose that in cases B$,$ C$,$ and D$,$ each combination of springs were replaced by a single spring such that the motion of the block is the same as before the replacement. We will call the spring constant of this new spring the effective spring constant of the original combination. Quantitatively, the effective spring constant, Keff, may be defined by the relationship is the sum of all forces on the block by the springs and x is the position of the block with respect to teh equilibrium position. Rank the four cases according to keff fro largest to smallest.