The statement that provides a possible explanation for the measured current being higher than the expected current is: "The circuit has an extra resistor."
In general, if a circuit has an extra resistor, it could potentially lead to an unexpected change in the current flow, but it is more likely that other variables (like changes in resistance or voltage) would need to be considered for an increase in current. However, since the options provided do not explicitly mention a decrease in resistance as a possible factor, the inclusion of an extra resistor could disrupt circuit balance and potentially explain the higher current.
Therefore, if we consider that the presence of an extra resistor could alter the expected current readings, that is the most fitting response from the given options.