Two point charges are fixed on the \(x\)-axis: a charge \(+Q\) is located at \(x = 0\) and a charge \(-4Q\) is located at \(x = d\), where \(d > 0\). Which of the following correctly identifies the position on the \(x\)-axis where the net electric field is zero, and the direction of the net electric field at \(x = 2d\)?