If $1^{\circ}=\alpha$ radians, then the approximate value of $\cos \left(60^{\circ} 1^{\prime}\right)$ is

• A

  $\frac{1}{2}+\frac{\alpha \sqrt{3}}{120}$
• B

  $\frac{1}{2}-\frac{\alpha}{120}$
• Correct answer
  C

  $\frac{1}{2}-\frac{\alpha \sqrt{3}}{120}$
• D

  $\frac{1}{2}+\frac{\alpha}{120}$

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