Final answer:
Primo Levi's 'free words' refers to words that have lost or changed their meaning at Auschwitz due to the harsh realities and conditions of prisoner life in the Holocaust.
Step-by-step explanation:
The term "free words" as referred to by Primo Levi, pertains to c. words that have lost or changed their meaning at Auschwitz.
During the Holocaust, in concentration camps like Auschwitz, everyday language often took on different or diminished meanings due to the oppressive and dehumanizing conditions the prisoners were subjected to. Words related to freedom, hope, and dignity were particularly affected as the reality of the prisoners' lives stood in stark contrast to what these words traditionally signify.