The following information is available from the books of XYZ Ltd:

Period Sales $($Rs$.)$ Profit $($Rs$.)$

I $1,10,0006,000$

II $1,30,0009,000$

Fixed costs are Rs$.30,000.$ Assuming that cost structure and selling prices remain the same in Periods I and II$,$ the sales required to earn a profit of Rs$.15,000$ is calculated as:

a$.$ Rs$.50,000$

b$.$ Rs$.45,000$

c$.$ Rs$.55,000$

d$.$ None of these