The length of a potentiometer wire is `600 cm` and it carries a current of `40 mA`. For a cell of emf `2V` and internal resistance `10Omega`, the null point is found to be ast `500 cm`. On connecting a voltmeter acros the cell, the balancing length is decreased by `10 cm`
The voltmeter reading will be
A. `1.96V`
B. `1.8V`
C. `1.64V`
D. `0.96V`