Maria works in a hardware store. A bin of aluminum nails and a bin of iron nails are knocked over, and the nails get mixed up. Both sets of nails are the same color and size.
What makes separating the nails a fairly easy job?

A. Aluminum is heavier and iron is lighter.
B. Iron settles in water, while aluminum floats.
C. Aluminum is magnetic, and iron is non-magnetic.
D. Iron is magnetic, and aluminum is non-magnetic.

Aluminum and iron are both metals; additionally, these materials are similar in color. However, because they are different elements they have different properties, this includes their weight as iron is heavier than aluminum; their melting point as iron has a higher melting point and their magnetic properties. Indeed while the iron is magnetic aluminum is non-magnetic, this means, aluminum does not stick to magnets. According to this, Maria could separate aluminum and iron nails using a magnet, this is fairly an easy job because iron is magnetic, and aluminum is non-magnetic.