For common emitter transistor amplifier, the audio signal voltage across the collector resistance of $2\mathrm{ }\mathrm{k}\mathrm{\Omega }$ is $\mathrm{4\; V.}$ If the current amplification factor of the transistor is $100$ and the base resistance is $1\mathrm{ }\mathrm{k}\mathrm{\Omega }$ then the input signal voltage is

• A

  $10\text{mV}$
• Correct answer
  B

  $20\text{mV}$
• C

  $30\text{mV}$
• D

  $15\text{mV}$

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