Let \\\\(x\\\\) be the oxidation number of \\\\(Ni\\\\) in \\\\(Ni(CO)_4\\\\).Since the overallcharge on the complex is \\\\(0\\\\), the sum of oxidation states of all elements init should be equal to \\\\(0\\\\).Therefore, \\\\(x + 4 (0) = 0\\\\)Hence, \\\\(x = 0\\\\).Thus, the oxidation number of \\\\(Ni\\\\) in \\\\(Ni(CO)_4\\\\) is \\\\(0\\\\).Hence, the correct option is \\\\(\ ext{B}\\\\)