Correct Answer - Option 2 : 0.0124/unit

p.u. value = Actual value/ base value

Z_{base} = V^{2}/S

Voltage rating on low voltage side (V) = 110 V

VA rating (S) = 2.5 kVA

\({Z_{base}} = \frac{{{{110}^2}}}{{2500}}\)

Per unit value \( = \frac{{0.06 \times 2500}}{{{{110}^2}}} = 0.0124\)