Answer
$A^+$ is the strongest oxidizing agent while $D^{3+}$ is the weakest.
Work Step by Step
A substance with a positive reduction potential $E^0(V)$ is a strong oxidizing agent. Conversely, a substance with a negative reduction potential $E^0(V)$ is a weak oxidizing agent.
A substance with more positive $E^0(V)$ is a stronger oxidizing agent.
A substance with more negative $E^0(V)$ is a weaker oxidizing agent.
