Treasury stock can be defined as

a. unissued stock, that is shares that have never been sold by the corporation.
b. designated stock, that is shares used for the specific purpose of converting preferred stock to common stock.
c. investment stock, that is shares acquired from a subsidiary company.
d. reacquired stock, that is outstanding shares purchased on the open market by the issuing corporation.
e. reacquired stock, that is outstanding shares purchased on the open market by the Treasury.

D