Answer:
According to Rachel, the major problem for the memory theory of personal identity is what? That somehow the establishments of associations between A=B and B=C don't equal A=C even though there is a very clear association between the elements.
Step-by-step explanation:
First of all, this is a very clear association problem and failure, which proves that the theory is highly ineffective or at least very questionable. Every time we found an association between elements a-b, b-d, x-t, or [-* we say that both are related because they share characteristics that make us group them in the same category. But when we find that A is equal or associated to B and at the same time that same B second element is equal or associated to a third new element called "C" we understand that the three of them share characteristics, values, forms or things that make us find similitudes between them, however in this case association isn't followed or respected so it's highly wrong. And that is why she considers this is the major problem of the theory because it doesn't respect the established patterns of association.