28.
A:
First dimension is isoelectric focussing followed by Native polyacrylamide gel electrophoresis
B:
First dimension is isoelectric focussing followed by SDS polyacrylamide gel electrophoresis
C:
First dimension is Native polyacrylamide gel electrophoresis followed by isoelectric focussing
D:
First dimension is SDS polyacrylamide gel electrophoresis followed by isoelectric focussing
The answer is: B