The resultant of two forces has a magnitude 1 N. One of the forces has a magnitude of $\sqrt{3}$N and makes an angle of $30°$ with the resultant. The magnitude of the other force is        

• A

  $1/2 \mathrm{N}$

• B

  $1 \mathrm{N}$

• C

  $\sqrt{3} \mathrm{N}$

• D

  $\frac{\sqrt{3}}{2}\mathrm{N}$