42. 當病人患有後天性心臟病和有心雜音,胸部X光出現心臟左上側雙層外觀(double contour or double convexity),明顯的左心房膨大,右心室肥大,最可能的診斷為: (A)主動脈瓣狹窄(aortic valve stenosis) (B)二尖瓣狹窄(mitral stenosis) (C)肺動脈瓣狹窄(pulmonary valve stenosis) (D)三尖瓣狹窄(tricuspid stenosis)