Eight teachers, P, X, Q, Z, R, B, C and S, are sitting around a square table, facing the centre of the table. Four of them are sitting at the corners, while four are sitting at the exact centre of the sides. Q is sitting exactly between R and S. C and S are diagonally opposite to each other. X is sitting exactly between B and S. C is sitting exactly between P and Z. R is sitting at the immediate right of Z. Who is sitting at the immediate right of C?