Let $A B C$ be an equilateral triangle with side length a. Let $R$ and $r$ denote the radii of the circumcircle and the incircle of triangle $A B C$ respectively. Then, as a function of $\alpha$ the ratio $\frac{R}{r}$

• A

    strictly increases
• B

   strictly decreases
   
• Correct answer
  C

  remains constant
   
• D

  strictly increases for $a<1$ and strictly decrease for $a>1$

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