A fixed point charge \(+Q\) is located at the origin of a coordinate plane. A rigid, nonconducting, frictionless rod is fixed horizontally along the line \(y = d\). A small bead of mass \(m\) carrying a positive charge \(+q\) is constrained to slide along the rod. The bead is released from rest at position \(A\) with coordinates \((d, d)\) and slides along the rod past position \(B\) with coordinates \((2d, d)\). Which of the following claims and justifications correctly describes the total mechanical energy of the bead-charge system as the bead moves from position \(A\) to position \(B\)?