Among four students, Alex, Brian, Clara, and David, Alex is older than Brian but younger than Clara. David is younger than Clara. Who is the youngest?

B. BRIAN

In a family, there are four members: a father, a mother, a son, and a daughter. The father is not the son. The mother is not the daughter. Who is the son?

C. SON

In a circular seating arrangement, A is sitting to the immediate left of B, and C is sitting to the immediate right of B. If D is sitting opposite to A, who is sitting to the immediate right of C?

D. D

Five friends P, Q, R, S, and T are sitting in a row. P is to the left of Q but not next to R. S is sitting next to T. Who is sitting in the middle?

B. Q

In a linear arrangement, M is taller than N but shorter than O. P is shorter than M but taller than Q. If R is the shortest, who is the tallest?

C. O