In a group of five friends: A, B, C, D, and E, A is taller than B but shorter than C. D is shorter than E but taller than A. Who is the tallest among them?

D. E

A, B, C, D, and E are five students. A is older than B but younger than C. D is older than E but younger than A. Who is the youngest?

B. B

In a puzzle involving six animals: Lion, Tiger, Bear, Elephant, Giraffe, and Zebra, the selection rules are: 1) Only mammals can be selected. 2) The Lion and Tiger must be included together or not at all. 3) The Giraffe cannot be selected if the Bear is selected. Which animals can be selected?

B. LION, TIGER, ELEPHANT

From the following items: X, Y, Z, A, and B, the selection rules are: 1) X and Y cannot be selected together. 2) If A is selected, then B must also be selected. 3) Z can be selected only if Y is not selected. Which of the following selections is valid?

C. X, Z

A class consists of six students: P, Q, R, S, T, and U. The selection criteria are: 1) P cannot be selected if Q is selected. 2) R must be selected if S is selected. 3) T can be selected only if U is not selected. Which of the following combinations is valid?

C. R, S, T