In a voltmeter there are 20 divisions between the 0 mark and 0.5 mark. The least count of the voltmeter is

Question

$\begin{array}{1 1} (a)\; 0.020 V \\ (b)\; 0.025 V \\ (c)\; 0.050 V \\ (d)\; 0.250 V\end{array}$