Which of the following is an example of a transitional metal and its common oxidation state?

Iron is indeed classified as a transition metal and has common oxidation states of +2 and +3. Transition metals are characterized by their ability to adopt multiple oxidation states due to the involvement of their d orbitals in bonding. Iron, specifically, is known to form ions with a +2 charge (ferrous) and a +3 charge (ferric), which are common in various chemical reactions, including redox processes and complex formations.

The other elements mentioned do not fit the criteria as well. Copper, for instance, typically has oxidation states of +1 and +2, so while its +1 state is common, it's not as broadly encompassed in the transition metal category like iron's multiple states. Zinc, while a d-block element, typically exhibits a +2 oxidation state, not +4, and is not regarded as a true transition metal since it doesn't have multiple oxidation states. Silver has a common oxidation state of +1, rather than +2, which further indicates it does not fit into the typical transition metal category as well as iron does.