A voltmeter of resistance $R$ is to be used to measure the potential difference across a resistance ' $r$ '. In which case the reading will be nearest to that in the absence of voltmeter?

• A

  $R < r$
• B

  $R>r$
• C

  $R=r$
• Correct answer
  D

  $R=0$

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