Shown in the figure is a meter-bridge setup with null deflection in the galvanometer. One resistor is $55\Omega$ and the balancing length from left is $20\text{cm}$. The value of the unknown resistor $R$ on the right side is:

1. A
   $13.75\Omega$
2. B
   $220\Omega$
3. C
   $110\Omega$
4. D
   $55\Omega$