A message signal of frequency $f_m$ is used to modulate a carrier of frequency $f_c.$ If the side bands are $f_1$ and $f_2$ then the ratio $\frac{f_c}{f_m}$ is

• Correct answer
  A

  $\left|\frac{f_1+f_2}{f_2-f_1}\right|$
• B

  $\frac{{\left(f_1+f_2\right)}^2}{f_1{f}_2}$
• C

  $\left|\frac{f_1-f_2}{f_2+f_1}\right|$
• D

  $\frac{f_1{f}_2}{{\left(f_1+f_2\right)}^2}$

Hence, the correct answer is option: 'A'.