The correct answer is A. Series.
An ammeter is a device used to measure electric current in a circuit. It is connected in series with the circuit element whose current we wish to measure. This means that the ammeter is placed directly in the path of the current. The ammeter has a very low resistance, so it does not significantly affect the current in the circuit.
If the ammeter were connected in parallel with the circuit element, it would have a high resistance and would significantly affect the current in the circuit. This is because the current would have to flow through the ammeter twice, once through the circuit element and once through the ammeter.
Option B is incorrect because an ammeter is not connected in parallel with the circuit element. Option C is incorrect because an ammeter is only connected in series with the circuit element. Option D is incorrect because an ammeter is connected in series with the circuit element.