Explaining the Name of the Theory. Consider both terms in the name of the "multiplier-accelerator" theory The accelerator refers to the OA. relationship between investment and the change in the rate of GDP. OB. Impact of consumption spending on the change in the rate of investment C. Impact of investment spending on GDP OD. fact that investment depends on the change (or acceleration) in the rate of investment The multiplier refers to the OA. Impact of investment spending on GDP B. relationship between investment and the change in the rate of investment. OC. relationship between investment and the change in the rate of GDP. D. Impact of consumption spending on the change in the rate of investment.