An Ac Circuit Has a 100- $\Omega$ Resistor in Series with A

Multiple Choice

An ac circuit has a 100- $\Omega$ resistor in series with a $4.9 - \mu \mathrm { F }$ capacitor and a $700 - \mathrm { mH }$ inductor. At what frequency does the circuit act like a pure resistance?

A) $86 \mathrm {~Hz}$
B) $0.29 \mathrm { MHz }$
C) $12 \mathrm { MHz }$
D) $1.9 \mathrm { MHz }$
E) $0.54 \mathrm { kHz }$