What is the difference between UX, CX, and BX?

I have been researching the relationship between User Experience (UX), Customer Experience (CX), and Brand Experience (BX) and found different definitions.

• One says UX is the subset of CX and CX is a subset of BX.
• One says partial of them are intersected.
• One says CX is the biggest unit, not BX.

Which concept is correct?