Three identical, uncharged conducting spheres (
\(A\), \(B\), and \(C\)) are mounted on insulating stands, with \(A\) and \(B\) touching each other and \(C\) isolated far away. A positively charged rod is brought near sphere \(A\) without touching it. While the rod remains near sphere \(A\), sphere \(C\) briefly touches sphere \(B\) and is then moved far away. Spheres \(A\) and \(B\) are subsequently separated, and finally, the charged rod is removed. Which of the following correctly identifies the signs of the final net electric charges on sphere \(A\) and sphere \(C\)?