Though the outer electronic configuration is same for the elements in 1B or 11th group Cu, Ag, & Au, gold and silver are less reactive than copper because 

• A

  Cu has less ionization energy than silver and gold

• B

  The higher effective nuclear charge due to poor shielding effect of inner d-electrons in Ag, and d & f electrons in Au make them more difficult to oxidize Ag & Au

• C

  The valence electron orbital energies of most common Lewis bases match the valance orbitals of Cu and its cations more closely and would interact with them more favorably to form products.

• D

  Heat of atomization of Ag and Au are more than Cu