the classification of personality disorders was based on the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition). In the DSM-5, Multiple Personality Disorder was referred to as Dissociative Identity Disorder (DID).
DID is not classified under any of the three clusters (A, B, or C) in the DSM-5. Instead, it is categorized as a dissociative disorder in its own right. Dissociative disorders involve disruptions or breakdowns of memory, consciousness, awareness, identity, and perception of the self and the environment.
It's important to note that classifications and diagnostic criteria may change over time, so I recommend consulting the latest version of the DSM or seeking the advice of a mental health professional for the most up-to-date and accurate information.