In an RLC circuit a second capacitor is added in series to the capacitor already present.

(a) Does the resonance frequency increase, decrease, or stay the same?

(b) Choose the best explanation from among the following:

I. The resonance frequency stays the same because it depends only on the resistance in the circuit.

II. Adding a capacitor in series increases the equivalent capacitance, and this decreases the resonance frequency.

III. Adding a capacitor in series decreases the equivalent capacitance, and this increases the resonance frequency.