To determine the value of current required for the full-scale deflection of a voltmeter, we need to understand the concept of voltmeter sensitivity. The sensitivity of a voltmeter is given as 125 Ohms/Volt, which informs us how much resistance the voltmeter has per volt of measurement.

In general, the sensitivity (\(S\)) of a voltmeter is defined as the reciprocal of the full-scale current.

The relationship is expressed as:

\(S = \frac{1}{I_{\text{full-scale}}}\)

Here, \(I_{\text{full-scale}}\) is the current required for full-scale deflection.

Given that sensitivity \(S = 125 \, \Omega/\text{V}\), we can rearrange the formula to solve for \(I_{\text{full-scale}}\):

\(I_{\text{full-scale}} = \frac{1}{S} = \frac{1}{125 \, \Omega/\text{V}}\)

First, convert Ohms/Volt into mA:

\(I_{\text{full-scale}} = \frac{1}{125} \text{ A}\)

Since the options are given in mA, convert the current from amperes (A) to milliamperes (mA):

\(I_{\text{full-scale}} = \frac{1}{125} \times 1000 \text{ mA} = 8 \text{ mA}\)

Thus, the current required for the full-scale deflection of the voltmeter is 8 mA.

This matches the correct answer in the given options: \(8 \, \text{mA}\).