Step-by-step explanation:
When a metal replaces another metal in solution, we say such a reaction has undergone a single displacement reaction.
In such a reaction, metal higher up in the activity series replaces another one due to their position.
To known the metal or metals that will replace the given copper, we need to reference the activity series of metals.
Every metal higher than copper in the series will displace copper from the solution.
So, there metals are: potassium, sodium, lithium, barium, strontium etc.