The correct options should be either option A. silver (or D. copper) as both metals can be found in the free state in nature. However, metals found in their free state in nature are typically the least reactive metals, often called noble metals, which do not readily combine with oxygen, water, or other elements in the atmosphere to form compounds. Based on this, we should go for option A since Silver is less reactive when compared to copper.

B. Zinc: is a moderately reactive metal. It readily reacts with other elements and is found in nature as compounds like zinc sulphide (zinc blende). It is never found in a free state in large amounts.

C. Iron: is more reactive than zinc and copper. It easily oxidizes (rusts) in the presence of air and moisture, so it is almost exclusively found in nature as iron oxides (ores like haematite and magnetite).