Correct Answer - Option 1 : 20 kΩ/V

__Concept:__

Sensitivity of voltmeter is given by,

\(s = \frac{1}{{{I_{FSD}}}}\)

Where I_{FSD} is full-scale deflection.

__Calculation:__

Given:

Full-scale deflection current, \({I_{FSD}} = \frac{1}{s} \)

Where, (s) is sensitivity.

\(s = \frac{1}{{{I_{FSD}}}}\)

\(s = \frac{1}{{50 \times {{10}^{ - 6}}}} = 20k{\rm{\Omega }}/V\)