As shown in the figure, the work done to move the charge ' $Q$ ' from point $C$ to point D along the semi-circle CRD is

• A

  $\frac{\mathrm{qQ}}{4 \pi \varepsilon_0 \mathrm{~d}}$
• B

  $\frac{\mathrm{qQ}}{2 \pi \varepsilon_0 \mathrm{~d}}$
• Correct answer
  C

  $\frac{-q \mathrm{Q}}{6 \pi \varepsilon_0 \mathrm{~d}}$
• D

  $\frac{-\mathrm{qQ}}{4 \pi \varepsilon_0 \mathrm{~d}}$

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