The effective rate which is equivalent to a nominal rate of 10% compounded semi-annually is:

10.25%

The correct answer is Option (4) → 10.25%

$\text{Nominal rate} = 10\%,\quad \text{compounded semi-annually}$

$\text{Effective rate} = \left(1 + \frac{0.10}{2}\right)^2 - 1$

$= (1.05)^2 - 1 = 1.1025 - 1 = 0.1025$

$\text{Effective rate} = 10.25\%$