I think it is the shortened way of saying it.
Answer:
C. "Getting lost" refers to the sensation of losing one's self in a group and even after, shortly affecting memory and self-image.
Explanation:
The idea of "getting lost" in a group can most definitely mean that a person has lost his personal values and beliefs by joining a group and adapting to the values of the group.
When a person loses himself in a group, he loses his self-image and he feels disillusioned.
Interest
Note: I am not 100%
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