A battery with negligible internal resistance powers a single resistor. When a real ammeter is inserted in series to measure the current, which of the following best describes the current the ammeter registers compared with the current that flowed before the meter was added, and the reason for the difference?
(a) The measured current is unchanged, because a properly designed ammeter has negligible effect on the circuit it measures.
(b) The measured current is smaller, because the ammeter adds resistance to the circuit.
(c) The measured current is smaller, because the ammeter diverts some of the charge through a separate path.
(d) The measured current is smaller, because an ammeter is designed with a very large resistance that greatly reduces the circuit current.