For n -point sets K in an LCA group Γ we obtain estimate for the norm of “the best” extension operator from space l∞(K) bounded functions on to A(Γ) Fourier transforms. As a simple consequence our implies that if is infinite closed subset then there does not exists linear C0(K) continuous vanishing at infinity A(Γ). The latter result generalises by Graham who considered case compact subsets K.