Answer:
C) plastic
Step-by-step explanation:
We know that like charges repel each other and unlike charges attract each other. When plastic ball is rubbed with fur, it could attract a positively charged pith ball. This means that the plastic ball gained electrons from the fur and became negatively charged.
When a glass rod is rubbed with fur, it could repel the same positively charged pith ball. This means glass rod lost electrons to the fur and became positively charged.
From this, we can conclude that most likely plastic could readily gain electrons.