A box contains red, blue, and green balls. If the selection criteria are to choose only blue or green balls, which of the following selections is valid?
In a group of five friends: Alice, Bob, Charlie, David, and Eva, Alice is taller than Bob but shorter than Charlie. David is shorter than Eva but taller than Bob. Who is the tallest among them?
A group of students consists of John, Lisa, Mark, and Sarah. John is older than Lisa but younger than Mark. Sarah is younger than Lisa. Who is the youngest student?
A set of cards is labeled with the names: Red, Blue, Green, and Yellow. The Red card is not next to the Blue card. The Green card is next to the Yellow card. Which card is next to the Blue card?