Determine AU(C'UB')

U= {a,b,c,d,e,f,g,h,i,j,k}
A= {a,c,d,f,g,i}
B={b,c,d,f,g}
C={a,b,f,i,j)

C' = {c,d,e,g,h,k}

B' = {a,e,h,i,j,k}
C'UB' = {a,c,d,e,g,h,i,j,k}
AU(C'UB') = {a,c,d,e,f,g,h,i,j,k} = {b}'