A straight uniform wire of resistance $36 \Omega$ is bent in the form of a semi-circular loop. The effective resistance between the ends of the diameter of the semi-circular loop is

• A

  $\frac{56}{9} \Omega$
• B

  $\frac{36}{7} \Omega$
• C

  $\frac{99}{7} \Omega$
• Correct answer
  D

  $\frac{77}{9} \Omega$

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