Final answer:
E. Aluminum (Al) would undergo oxidation the easiest among the options given, as it is higher on the activity series and has a higher reactivity.
Step-by-step explanation:
The student asked which element would undergo oxidation the easiest among Cd, Cu, Ag, Zn, and Al. Referring to the activity series, we can determine the relative reactivity of metals with respect to oxidation. Elements higher on the activity series oxidize more easily. Among the given options, aluminum (Al) is higher on the activity series compared to the other elements listed, making it the most likely to undergo oxidation the easiest. This is due to its higher reactivity, as indicated by its more negative standard reduction potential (Eº = −2.07 V) compared to other metals like zinc (Zn) which has a Eº of −1.476 V, suggesting that aluminum prefers to lose electrons and form Al3+ ions.