Final answer:
Arturo Escobar is a thinker who works on Post-Development theory, challenging universal structures and advocating for a variety of local understandings over a single narrative of progress.
Step-by-step explanation:
According to the article in The Guardian, Arturo Escobar is a thinker who primarily works on the theory of B.Post-Development. Post-Development theory is a critique of conventional notions of development and progress. Post-Development thinkers argue against universalisms and homogenizing efforts of development, suggesting that the world cannot be interpreted through preexisting structures, as there is no single, objective truth or universal narrative that can account for the complexities and diversities of human experiences. They propose instead a multiplicity of local and contextual understandings and actions. Therefore, the correct answer to the question is B.Post-Development.