In $\triangle A B C$, if $\mathrm{A}=60^{\circ}$ and $\mathrm{B}=105^{\circ}$ then $$ \begin{aligned} & \frac{2 \mathrm{R}^2(b-c) \sin \mathrm{A} \sin \mathrm{B} \sin \mathrm{C}}{(b+c)(s-a \cos \mathrm{C}-c \cos \mathrm{A})(\mathrm{s}-a \cos \mathrm{B}-b \cos \mathrm{A})}= \\ \end{aligned} $$

• A

  $\frac{1}{\sqrt{2}}$
• B

  $\sqrt{3}$
• Correct answer
  C

  1
• D

  $\frac{1}{\sqrt{3}}$

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