which one is ans for a) and b)?

The above is for A

For B, my apology I miss out, here's the answer.
Prepare three test tube in a test tube rack, add metal of each sample to test tube respectatively. Add sodium hydroxide solution to each of the test tube.

Solutions containing copper(II) ions will form a blue precipitate with sodium hydroxide. With the colour, we will know each contain copper(ii) ion.

oh okay thank you :)