R = 7.4 Ω
L = 3H
C = 27 μF = 27 x 10-6 F
The resonant angular frequency ω0 is given by

The simplest way to improve the sharpness of the resonance of the circuit is by reducing its full width at half maximum by a factor of 2 is to reduce the value of R to \(\frac{R}{2}\) i.e. by making
\(R = \frac{7.4}{2}= 3.7\Omega\)