An ammeter should have ___________ resistance.

The correct answer is C. Very low.

An ammeter is a device used to measure electric current. It is connected in series with the circuit being measured, so that the current flows through the ammeter. The ammeter should have a very low resistance so that it does not affect the current being measured.

If the ammeter had an infinite resistance, no current would flow through it, and it would not be able to measure the current.

If the ammeter had a very large resistance, it would affect the current being measured, and the reading would not be accurate.

Therefore, the ammeter should have a very low resistance.