Explanation:

- To find the compound interest, we use the formula:

$$ A = P \left(1 + \frac{r}{n}\right)^{nt} $$

where:

\( A = \) the future value of the investment/loan, including interest

\( P = 8000, \) the principal investment amount

\( r = 0.05, \) the annual interest rate

\( n = 4, \) the number of times interest applied per year

\( t = 0.25, \) the time the money is invested for in years (3 months = 0.25 years)

- Calculate:

$$ A = 8000 \left(1 + \frac{0.05}{4}\right)^{4 \times 0.25} $$

$$ A = 8000 \left(1 + 0.0125\right)^1 $$

$$ A = 8000 \times 1.0125 = 8100 $$

- Compound Interest = \( A - P = 8100 - 8000 = 100 \)

- Option:1 Rs100 – Correct

- Option 2: Rs150 – Not correct

- Option 3: Rs80 – Not correct

- Option 4: Rs120 – Not correct