The correct response is:
The electrons will move and spread out through the cup and to the can. This is because the styrofoam cup is a conductor.
However, it's important to note that styrofoam is generally considered an insulator, not a conductor, which makes it less likely for the electrons to spread out through it. The metal can, on the other hand, is a conductor and allows for the movement of electrons.
In this scenario, when the negatively charged balloon is brought near the styrofoam cup, the electrons in the can (since the can is a conductor) will feel the effect of the negative charge and could redistribute. However, the movement will be limited because the cup itself is an insulator and does not conduct electrons. Thus, the most accurate understanding is that the electrons will respond primarily through the can rather than the cup. If you have a specific answer key in mind, ensure the nature of the materials (conducting/insulating) aligns with standard physics principles.