Why were gold and copper the first forms of matter investigated by humans

The answer for #3 is c but i don't know why

Why does a red shoe appear red in daylight

Which statements are true about electrolysis? check all that apply. electrolysis requires an acid be present. electrolysis is described by two half-reactions. electrolysis is not an industrial process. electrolysis results in commercially valuable products. electrolysis involves the transfer of electrons. reduction results in the loss of electrons. oxidation results in the loss of electrons.