Consider the following statements regarding the advantages of closed-loop negative feedback control-systems over open-loop systems:

I. The overall reliability of the closed-loop systems is more than that of open-loop system.

II. The transient response in the closed-loop system decays more quickly than in open loop system.

III. In an open-loop system, closing of the loop increases the overall gain of the system.

IV. In the closed-loop system, the effect of variation of component parameters on its performance is reduced.

Of these statements: