What is slave b?

There is no specific information to answer this question, as it depends on the context and time period in which the term "slave B" is being used. Generally, the term "slave" refers to a person who is legally and economically owned by another person, and who is forced to work without pay or freedom. The term "slave B" could refer to a specific individual who was enslaved, or it could be used to differentiate between different types or classes of slaves. Without more context, it is difficult to provide further information.