Who among the following is known as a post-Marxist thinker?

The correct option is Ernest Laclau.

Understanding Post-Marxism:
Post-Marxism is a school of political philosophy and social theory that emerged in the late 20th century. It seeks to move beyond the traditional tenets of classical Marxism, particularly its economic determinism (the view that the economic base completely determines the social and political superstructure) and class reductionism (the view that all social conflict can be reduced to class struggle). Post-Marxist thinkers retain certain Marxist insights but integrate them with post-structuralism, discourse analysis, and the recognition of diverse social movements.

Ernesto Laclau's Contribution:
Ernesto Laclau (along with Chantal Mouffe) is widely recognized as one of the founding and most prominent figures of post-Marxism. In their seminal 1985 book, Hegemony and Socialist Strategy, Laclau and Mouffe systematically critiqued classical Marxist class reductionism. They argued that political identities and struggles are not pre-determined by economic class positions, but are instead constructed through discourse and political struggle. They emphasized that modern democratic struggles involve a variety of social movements (such as feminism, environmentalism, and anti-racism) rather than just the working-class struggle.

Why other options are incorrect:
• Antonio Gramsci: He was an influential Italian Marxist philosopher and politician best known for his theory of cultural hegemony. He is classified as a Western Marxist or Neo-Marxist who laid the conceptual foundation for later post-Marxist developments, but he himself operated within the Marxist framework.
• Theodor Adorno and Walter Benjamin: Both were prominent members of the Frankfurt School of critical theory. They are classified as Western Marxists or Neo-Marxists, focusing on cultural and psychological critiques of capitalism, rather than post-Marxists.