Step 1: Understanding the question:
The question asks which thinker envisioned a society with no class divisions at all.
Step 2: Why option B is correct:
Karl Marx, founder of the conflict theory of stratification, argued that after the proletariat revolution abolishes private ownership of the means of production, society would pass through socialism into communism, a classless society with no exploitative class distinctions.
Step 3: Why the other options are wrong:
Gide and Rist were historians of economic doctrine, not theorists of a classless society; Henney is not a recognised sociological theorist on this theme; Engels was Marx's close collaborator but the idea of the classless society is credited primarily to Marx himself.
Final Answer:
Marx (option ii).