The reactance of a circuit is zero It is possible that the circuit contains
(i) an inductor and a capacitor
(ii) an inductor but no capacitor
(iii) a capacitor but no inductor
(iv) neither an inductor nor a capacitor .

Explanation

There are two possibilities for the reactance to becomes zero. First may be the case when there is no inductor and capacitor connected in the circuit. And the seconed may be the case when both inductor and capacitor are connected but `(1)/(omega C) = omega`L .
It is not possible that only capacitor is present and no inductor or vice versa. Either both are absent or both are present with condition `(1)/(omega C ) = omega`L .