Pick the group of elements with the most common characteristics a) copper, oxygen, silver b) silver, iodine, helium c) oxygen, hydrogen, lithium d) copper, gold, silver

D!  Copper (Cu), Gold (Au), and Silver (Ag) are the most similar.  These three are all transition metals, and are found in the same group, 11 or 1B.  Due to the fact that these guys are all in the same group they're going to have the same number of valance electrons and similar properties.