Concept:Active voice focuses on the subject performing the action. Passive voice focuses on the action being done to the subject.Explanation:Check each option's structure:Option A: "will be caught" – passive (future simple).Option B: "know" – active (present simple).Option C: "is not taught" – passive (present simple).Option D: "was knocked" – passive (past simple).Only option B has the subject "I" directly doing the action "know".Answer:Option B: I know nothing about western philosophy.