Final answer:
The most common defense at the Nuremberg Trials was that defendants were only following orders from superiors, known as the 'Superior Orders' defense, which was ultimately not accepted by the tribunal. The correct answer is option: They had only been following orders from their commanding officers.
Step-by-step explanation:
The most common defense of the defendants at the Nuremberg Trials was that they had only been following orders from their commanding officers. This defense was known as the “Superior Orders” or "Befehl ist Befehl" ("an order is an order") argument.
However, this defense was generally not accepted by the International Military Tribunal, which held individuals accountable for their actions despite the orders they may have received. Many of the accused at Nuremberg were high-ranking Nazi officials who played significant roles in orchestrating the Holocaust and other war crimes. The trials resulted in several death sentences and long imprisonments for many principal perpetuators.