An ac generator `G` with an adjustable frequency of oscillation is used in the circuit, as shown.
To increase resonant frequency of the circuit, some of the changes in the circuit are carried out. Which changes would certainly result in the increase in resonnatn frequency ?
A. `R` is increased
B. `L_(1)` is increased and `C_(1)` is decreased
C. `L_(2)` is decreased and `C_(2)` is increased
D. `C_(3)` is removed from the circuit
