In reality what happens due to the interaction of the oblique shock waves with the boundary layer on the walls of the diffuser?

In reality what happens due to the interaction of the oblique shock wa

1.	In reality what happens due to the interaction of the oblique shock waves with the boundary layer on the walls of the diffuser?
A.	Higher total pressure loss
B.	Reduction of speed
C.	Total pressure increase
D.	Reduced skin friction drag
Answer» B. Reduction of speed