'Five litres of water is added to a certain quantity of pure milk costing Rs.3 per litre. If by

"Five litres of water is added to a certain quantity of pure milk costing Rs.3 per litre. If by selling the mixture at the same price as before, a profit of 20% is made, then what is the amount of pure milk in the mixture?
a. 20L
b. 25L
c. 30L
d. 35L"

litre.