Given a text passage, come up with an appropriate title for it. The title should accurately represent what the main focus of the passage is. The title of a passage may be present in the first few sentences of the passage and/or be referred to multiple times in the passage. The title should be 1-5 words long.

[Q]: According to A&E 's Biography , Bert and Ernie were virtually the only Muppets to appear in the Sesame Street pilot episode , which was screen tested to a number of families in July 1969 . Their brief appearance was the only part of the pilot that tested well , so it was decided that not only should Muppet characters be the `` stars '' of the show , but would also interact with the human characters , something that was not done in the pilot .
[A]: Bert and Ernie


[Q]: The Yellowstone Caldera is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States , sometimes referred to as the Yellowstone Supervolcano . The caldera and most of the park are located in the northwest corner of Wyoming . The major features of the caldera measure about 34 by 45 miles ( 55 by 72 km ) .
[A]: Yellowstone Caldera


[Q]: To Kill a Mockingbird is a novel by Harper Lee published in 1960 . It was immediately successful , winning the Pulitzer Prize , and has become a classic of modern American literature . The plot and characters are loosely based on Lee 's observations of her family , her neighbors and an event that occurred near her hometown of Monroeville , Alabama , in 1936 , when she was 10 years old .
[A]:
To Kill a Mockingbird