During the measurement of a low resistance using a potentiometer, the following readings were obtained: Voltage drop across unknown resistance = 0.531V. Voltage drop across a 0.1Ω standard resistance connected in series with the unknown = 1.083V. Value of the unknown resistor is

A

53.1 milliohm

B

49.03 milliohm

C

108.3 milliohm

D

20.4 milliohm