A series $LCR$ circuit is connected across a source of alternating emf of changing frequency and resonates at frequency $f_0$. Keeping capacitance constant, if the inductance (L) is increased by $\sqrt 3$ times and resistance is increased (R) by 1.4 times, the resonant frequency now is

Question

$$(a)\;3^{1/4}f_0 \quad (b)\;\sqrt 3 f_0 \quad (c)\;(\sqrt 3-1)^{1/4} f_0 \quad (d)\;\bigg(\frac{1}{3}\bigg)^{1/4}f_0$$