Final answer:
Using the activity series to determine the order from most to least active, we find that magnesium (Mg) is more active than zinc (Zn), which in turn is more active than lead (Pb), making option (c) the correct answer.
Step-by-step explanation:
To arrange Pb (lead), Mg (magnesium), and Zn (zinc) from the most active to the least active, let's refer to the activity series which ranks elements based on their tendency to be oxidized. Magnesium is located above zinc in the series, indicating that it has a greater tendency to lose electrons and hence is more active. Zinc will react with both copper salts and silver salts, but it will not react with magnesium salts, meaning zinc is less active than magnesium but more active than other metals like copper or silver that are lower in the series. Lead is even further down the list, being less active than both magnesium and zinc. Therefore, the correct order from most active to least active is Mg, Zn, Pb, which corresponds to option (c).