Answer
Negatively charged
Work Step by Step
When you approach the positively charged rod to the two neutral metal spheres, the electron will travel toward the rod.
This will make the right side positively charged since the atoms there lose some electrons and that makes them positive ions.
See the figure below.
This means that the side that is facing the rod will be negatively charged while the other side is positively charged.
Therefore, sphere A is now negatively charged.
