What sharing option can be used to provide customers with read and edit access to their own accounts only?

The option that provides customers with read and edit access to their own accounts only is the Private External Sharing Model. This model is specifically designed for external users in communities, enabling them to have access to their own records without exposing other records.

In this model, external users can see and edit only the data associated with their own accounts, ensuring a high level of data security and privacy. This setup is particularly beneficial in scenarios where users need to manage their own account details or engage with specific process flows without being able to view or edit any other users' accounts.

The Public Sharing Model would grant broader access, allowing users to see more records than just their own, which is not suitable for this requirement. Role Hierarchy Access is based on the organization’s internal roles and would not limit access to only one's records. Community Sharing Sets can provide access to multiple records based on defined criteria but still do not specifically limit a user to just their own account, as required by the question.