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

The correct option is Ernest Laclau.

Explanation:
Post-Marxism is a theoretical trend that emerged in the late 20th century. It seeks to move beyond traditional Marxist orthodoxies—specifically economic determinism and class reductionism—while still retaining certain aspects of Marxist critique. Post-Marxists argue that social identity and political struggle cannot be reduced solely to class divisions or economic relations.

Ernesto Laclau, along with Chantal Mouffe, is widely recognized as one of the key figures of post-Marxism. Their seminal 1985 work, Hegemony and Socialist Strategy, is considered a foundational text of this school of thought. In this work, they deconstruct classical Marxist categories and emphasize the role of discourse, political hegemony, and diverse social movements (such as feminism, environmentalism, and anti-racism) in shaping political struggles, rather than relying solely on the working-class struggle.

Let's briefly look at the other options to understand why they do not fit the "post-Marxist" label:
1. Antonio Gramsci: Gramsci was an influential Italian Marxist theorist. He is best known for his theory of cultural hegemony, which explained how the ruling class maintains control. While his work heavily inspired later post-Marxist developments, Gramsci himself worked within the Marxist framework (often classified as Neo-Marxist or Classical Western Marxist).
2. Theodor Adorno and Walter Benjamin: Both were prominent members of the Frankfurt School, associated with Critical Theory. Their work focused on cultural critique, aesthetics, and sociology from a Neo-Marxist perspective, rather than the post-Marxist framework established later in the late 20th century.