The shortened ionic reaction equation Cu + 2OH → Cu (OH) 2 ↓ corresponds to the interaction of substances:

The shortened ionic reaction equation Cu + 2OH → Cu (OH) 2 ↓ corresponds to the interaction of substances: 1) barium hydroxide and copper sulfate 2 2) hydrochloric acid and copper hydroxide 2 3) sodium hydroxide and copper chloride 2 4) copper oxide 2 and nitric acid

The abbreviated ionic equation Cu + 2OH = Cu (OH) 2 indicates that the solution contained copper ions and hydroxide ions. Ions go into solution only if the substances are soluble (they are electrolytes).
This means that in the list of proposed substances, we must find a soluble copper salt (oxide and hydroxide are not electrolytes) and a soluble base.
These are sodium hydroxide and copper chloride (see table)
CuCl2 + 2NaOH = Cu (OH) 2 + 2NaCl
Cu + 2Cl + 2Na + 2OH = Cu (OH) 2 + 2NA + 2Cl
Cu + 2OH = Cu (OH) 2