Ans: C. Breath sound(Ref Harrison 19/e p1573, 1719, 18/e p1972)Raised JVP, pulse pressure and muffled hea sounds along with pulsus paradoxus are seen in both cardiac tamponade and tension pneumothorax.These are differentiated by auscultation for breath sounds, which are normal in cardiac tamponade but absent in tension pneumothorax patients.Pericardial Tamponade:The three principal features of tamponade (Beck's triad) are hypotension, soft or absent hea sounds, and jugular venous distention with a prominent x-descent but an absent y-descent.