A stock dividend increases the number of shares owned without affecting the total cost basis. The new cost basis per share is calculated by dividing the original total investment by the new number of shares:

Original total investment = 100 shares × $50.00 = $5,000

After a 10% stock dividend, the investor owns 110 shares.

New cost basis = $5,000 ÷ 110 shares = $45.45 per share.

B is correct because it reflects the adjusted cost basis per share.