The standard reduction potentials of three electodes P, Q and R are respectively – 1.76 V, 0.34 V and 0.8 V. Then

Lower SRP metal displaces Higher SRP metals from their salt solutions.Since SRP of P is least it displaces Q and R from their salt solutions.SRP of Q is lesser than R displaces R from its salt solution but doesnot displace P because its SRP is higher than PR does not displace  any of the given because its SRP is higher among all the  given.