: SDF: RD was horridly inspecific about the C-M-C transaction of the working classes. In real life, the first C is WORK-TIME.
Although in my mind I was thinking 'C=Labour Power', I have to admit that there are reasons for the inspecificity, because, we should also include artisan producers in the C-M-C complex, instead of selling their labour time, they sell their produce direct (such people now are rare, but plumbers, and some craftsfolk still remain at such status).
Technically shopkeepers come here as well (Small ones anyway), since they are selling to buy their means of living, and to replace their stock, the shift comes when money is invested to make more money.
In such sense the formula for Capital is more important, because the working class can be designated as 'not-the-capitalist-class', we can be specific about the people who live as M-C-M, and anyone who isn't, has a different interest.