A SP-A.

[Feedback :- Surfactant protein A is only marginally involved in lowering the surface, but does play an important role in the innate lung defence barrier against pathogenic organisms. Congenital absence of SP-B is lethal in the neonatal period.]

B SP-B.

This is the Correct Answer

[Feedback :- Congenital absence of surfactant protein B is lethal in the neonatal period.]

C SP-C.

[Feedback :- Surfactant protein C deficiency is not associated with respiratory failure at birth, but may lead to interstitial lung disease in later childhood. Congenital absence of SP-B is lethal in the neonatal period.]

D SP-D.

[Feedback :- Surfactant protein B is only marginally involved in lowering the surface but does play an important role in the innate lung defence barrier against pathogenic organisms. Congenital absence of SP-B is lethal in the neonatal period.]

E SP-E.

[Feedback :- There are four major surfactant proteins (A, B, C and D). Congenital absence of SP-B is lethal in the neonatal period.]