1What information are we to assumer 'the observer' has? Do they know the A/B/C tagged addresses are controlled by A/B/C? Do they know for certain which addresses are change addresses? In general, 'certainty' of blockchain analysis is a somewhat hopeless goal in the real world. – chytrik – 2018-10-12T23:08:28.973

Just out of curiosity, where does this question come from ? It's, strangely, identical to one of the HWs in one of my classes. – Shawn – 2018-12-02T22:37:30.223