An issuer of bonds uses a sinking fund for the retirement of the bonds. Cash was transferred to the sinking fund and subsequently used to purchase investments. The sinking fund

I. Increases by revenue earned on the investments.

II. Is not affected by revenue earned on the investments.

III. Decreases when the investments are purchased.

A.I and III. B.I only. C.II and III. D.III only

Could you explan why the sinking fund doesnt decrease when the investment is purchased?? Doesnt the withdrawl from bond sinking fund decreases the sinking fund?