Sam Stone was the owner of stock that cost him $50,000 when he acquired it in 2014. On January 1, 2015, when the stock was valued at $10,000, he made a bona fide gift of the stock to his niece, Ruth Rock. Ms. Rock held the stock until August 15, 2017, and then sold it for $60,000. What is the amount of the gain or loss that Ms. Rock should include in her adjusted gross income for 2017?

$0

$10,000 gain

$30,000 loss

$40,000 loss