Cardiac tamponade causes pulsus:

Ans: c (Paradoxus) Ref: Harrisons, 16th ed, p. 1416; 17th ed, p. 1491Clinical signs in cardiac tamponade - pulsus paradoxus, prominent x descent in JVPECG changes - low ECG voltage, electrical alternans. RVDC feature in echoNotesFreidrichs sign - Rapid fall (steep Y descent) and rise of JVP seen in constrictive pericarditis and tricuspid regurgitation.