Identify the structures marked as A, B, C and D in order - also specify what A, B, C constitute in the picture (choose the appropriate statement) :

Question

( a ) Alveolar wall, Fibrous tissue, Endothelium of alveolar capillaries, Red blood cells ; A, B, C constitute basal membrane
( b ) Alveolar wall (the thin squamous epithelium of alveoli), Fibrous tissue, Alveolar capillaries, Blood ; A, B, C constitute basal membrane
( c ) Alveolar wall, Fibrous tissue, Alveolar capillaries, Blood ; A, B, C constitute diffusion membrane
( d ) Alveolar wall (the thin squamous epithelium of alveoli), Basement substance, Endothelium of alveolar capillaries, Red blood cells ; A, B, C constitute diffusion membrane