In Any Given Period,a Firm's Flow of Investment Demand Is

In any given period,a firm's flow of investment demand is determined by

A) the change in the firm's optimal capital stock.
B) the rate of change of the capital stock in the entire economy.
C) the change in the firm's optimal flow of investment.
D) the rate of change of the firm's investment demand.
E) Any of the above,as they are all the same.