A triangular opacity with clear borders, base towards midline and obliterating right heart border on a chest radiograph suggest that the pathology is likely to be in -: (A) Apical segment of right lower lobe, (B) Medial segment of right lower lobe, (C) Right middle lobe, (D) Any of the above
Answer is C. Right middle lobe pathology obliterates lower right border of heart producing silhouette sign.