The best method for preparation of $Me_{3}\mathrm{CCN}$ is

• A

  to react $Me_{3} \mathrm{COH}$ with HCN
• B

  to react $Me_{3}$ CBr with NaCN
• Correct answer
  C

  to react $Me_{3} \mathrm{CMgBr}$ with CICN
• D

  to react $Me_{3} \mathrm{Cl}$ with $\mathrm{NH}_{2} \mathrm{CN}$

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