Treasury stock was sold above cost, and the excess was credited to gain on sale. this error would cause the period's a. net income to be overstated. b. end liabilities to be overstated. c. end stockholders' equity to be overstated. d. end assets to be overstated.

The correct answer is A. Net income to be overstated.

The excess amount should be recorded in the journal entry to debit cash and credit treasury stock then the paid-in capital from treasury  stock.

Let's say that the treasury stock was sold at above cost of $10,000 shares which we know that it is more than what is being paid to purchase, for example lets say it is $7 per share then the debit cash will be $70,000 and the treasury stock credit which is $60,000 which was before the added cost and the paid-in capital which is from treasury stock will be, ($70000 - $60,000) = $ 10,000.