Final answer:
The most likely reason the woman claims the abuse was a dream is that she is using avoidance as a defense mechanism to manage the anxiety caused by discussing her childhood abuse.
Step-by-step explanation:
The most likely reason for a 35-year-old woman, who is a survivor of childhood abuse, to claim that the abuse was a dream and actually never happened, is B. the client is using avoidance to manage anxiety brought up by discussing the abuse. This behavior can be understood as a psychological defense mechanism where the distress associated with the memories of abuse leads the person to attempt to distance themselves from the experience. This is consistent with the concept of repression, where anxiety-causing memories are blocked from consciousness to protect the individual from psychological distress. The phenomenon where traumatic memories are not recalled, or are inaccurately remembered, is well-documented in the literature regarding childhood abuse survivors.