Which of the following best explains why you sanded the copper wire before burning it? to create less friction between the copper and the tongsto make sure that copper metal was exposed on the surface of the wireto make the copper wire flammableto weaken the copper wire so it would be more reactive

Option (b) is the correct answer.

Explanation:

When copper wire is place into the atmosphere or anywhere then there is possibility that some oxide layer or impurity must have deposited over its surface.

So, when we sanded copper wire then these impurities get removed and copper metal gets exposed onto the surface.

Thus, we can conclude that you sanded the copper wire before burning it to make sure that copper metal was exposed on the surface of the wire.