Read the following article and answer the question. Article: Wherever she goes, Molly leaves her mark. Without saying a word, she speaks to people with her kind eyes. Even when she walks away, she leaves an impression.Molly's mark is a smile, stamped into the ground by the horseshoe at the bottom of her false leg. A few years ago, Molly was badly attacked by a dog.The dog bit all four of Molly's legs and left large cuts in her face. Molly's owner, Kate Harris, took her to an animal hospital.Doctors there were able to save Molly's life, but soon one of her legs became very infected . At first, doctors thought Molly would have to be put to sleep.But Molly changed their minds. This pony, doctors noticed, shifted her weight, and rested her good leg from time to time. Doctors knew that Molly had amazing intelligence, and that she wanted to live. Several doctors operated on Molly, and removed her infected leg. A false leg was made for her. The leg was a hollow cast with a pole at the bottom for balance. Doctors gave Molly a special horseshoe at the bottom of the leg. This horseshoe she had had a stamp of a smile face in it! After the operation, Molly walked around on all four legs, as if nothing had ever happened to her! Now, with every step she takes, she stamps a smile in the dirt.But she leaves her m ark in other ways, too. Kaye Harris took Molly to the false leg center. There were children there who, like Molly, had artificial arms or legs. They were amazed to see a pony with a false leg. Molly made them smile and gave them hope. Soon, Molly began to visit schools, nursing homes, army bases and hospitals. A book was even written about Molly! Question: Which is the best title for the passage? Answer:

Select from:
(I) A Book on Molly;
(II) A False Leg;
(III) A successful Operation;
(IV) Leaving her Mark;
Answer:
(IV)