Communication Systems - Engineering

Q1:

The tuned circuit of the oscillator in a simple AM transmitter employs a 50 H coil and a 1 nanofarad capacitor. If the oscillator output is the carrier frequency will be

A 448 kHz

B 555 kHz

C 625 kHz

D 712 kHz

ANS:D - 712 kHz

How it came? explain please.