Explanation :
We know that the resistance of the wire is given by :
[tex]R=\rho \dfrac{l}{A}[/tex]
Where
[tex]\rho[/tex] is the resistivity
l is the length of the wire
A is the area of the wire.
Another factor on which the resistance of wire depends is temperature. It is given by :
[tex]R=R_{ref}[1+\alpha (T-T_{ref})][/tex]
So, it is clear that the resistance of the wire is directly proportional to the temperature. It we want to decrease the resistance of the piece, its temperature should be decreased.
So, the correct option is (3) " decreasing the wire’s temperature ".
Decreasing the wire’s temperature decreases the resistance of a piece of copper wire.
Resistance is a type of opposition force due to which the flow of current is reduced in the material or wire. Resistance is the enemy of the flow of current.
The relation of resistance with length and thickness is given by ;
[tex]\rm R= \frac{\rho L}{A}[/tex]
The value of resistance is directly propotional to length and inversly propotional to the area or thickness of the wire.
As the value of temperature increases, the value of resistance in the material is increasing. Length, temperature, and thickness are the factors that affect the resistance of a material.
Resistance of the wire is directly propotional to the temperature. On decreasing the temperature the resistance of the wire is also decreasing.
Hence decreasing the wire’s temperature decreases the resistance of a piece of copper wire.
To learn more about the resistance refer to the link;
https://brainly.com/question/20708652