A solution consists of 50 litres of pure milk. 10 litres of milk is replaced with equal quantity of water. Again 10 litres of the mixture is substituted by 10 litres of water and this operation is repeated one more time. Find the quantity of milk in the final solution.

A

25.2 litres

B

25 litres

C

25.4 litres

D

25.6 litres