A 2 volt battery, a `15 Omega` resistor and a potentiometer of `100 cm` length, all are connected in series. If the resistance resistance of potentiometer wire is `5 Omega`, then the potential gradient of the potentiometer wire is
A. 0.005 V//cm
B. 0.05 V//cm
C. 0.02 V//cm
D. 0.2 V//cm