Rs. 108.25

Rs. 112.20

Rs. 124.75

Rs. 125.25

C. Rs. 124.75

For an income of Rs. 756, investment = Rs. 9000.

For an income of Rs. $\frac{21}{2}$ , investment = $Rs.\left(\frac{9000}{756}\times \frac{21}{2}\right)=Rs.125.$

$\therefore $ For a Rs. 100 stock, investment = Rs. 125.

Market value of Rs. 100 stock = $Rs.\left(125-\frac{1}{4}\right)=Rs.124.75$