As shown in figure (a) below, you touch a neutral (uncharged), isolated sphere of an unknown material with a positively charged rod. Then you remove the rod and bring another positively charged rod, suspended by a string near the left side of the sphere. You observe that the suspended rod is repelled by the sphere figure (b). When you bring the suspended rod near the right side of the sphere, it is not repelled or attracted figure (b).
Which of the following is the best explanation for your observations?