According to baddeley, which memory system is best conceived of as three interrelated systems: central executive, visual sketchpad, and auditory recorder?

I believe the answer is: Working memory

In Baddeley's system, he splits Working memory into multiple components rather than presenting it on one unified construct.
The multiple components in this system is very similar to the organizational structure that we observe in office environment, in which each components had their own role in regulating the flow of information in our memory.