The most well-known group of critical theorists formed the Frankfurt School in Germany. As also understood from the information given, the correct answer is A. Max Horkheimer, Theodor Adorno, Erich Fromm, Walter Benjamin, Jürgen Habermas, and Herbert Marcuse were among the core group at the Frankfurt School (the Institute for Social Research) beginning in the early 1920s). Kant, Schiller, and Hegel, as well as Nietzsche, Lukács, Weber, and Freud, inspired the critical perspective of the Frankfurt School.