The Cu-Ni system is an isomorphous one, meaning that the crystal structure does not change with alloying; in particular, Cu and Ni atoms randomly substitute for one another within a FCC crystal structure. This generates solid solution strengthening. A Cu-Ni alloy is desired that has a minimum tensile strength of 300 MPa and a minimum ductility of 35 %EL. Based on Fig. 9.6 (Callister 8e), select all possible compositions that meet these criteria C0 = 20 wt%Ni C0 = 40 wt%Ni C0 = 60 wt%Ni C0 = 80 wt%Ni