3. Using K-maps, obtain minimum POS expression for the following Boolean functions (a) (b) (c) F(X,Y,Z)=X-Y-Z+X-Y-Z+X-Y F(X,Y,Z)=X-(Y-Z+y.Z)+X-(Y-Z+Y-Z) F(X, Y,Z) = X + X-Z+X-Y+X-Y-Z