Treasury stock refers to shares that were issued by a company and subsequently repurchased by the company. These shares are held in the company’s treasury and are not considered outstanding.

C is correct because treasury stock is stock reacquired by the issuer.

A is incorrect because authorized but unissued stock has never been issued.

B is incorrect because restricted stock refers to shares issued with restrictions on transferability, not reacquired stock.

D is incorrect because it incorrectly refers to government securities, not corporate stock.