Explanation:

- Mixture A has a water to milk ratio of 4:1. This means, in 250 liters, there are 200 liters of water and 50 liters of milk.

- Mixture B has 25 liters of water. The water to milk ratio is 5:7. Therefore, the milk in B is $\frac{25\times 7}{5}=35$ liters.

- When 40% of Mixture A is taken, it means $0.4\times 250=100$ liters are mixed, resulting in 80 liters of water and 20 liters of milk.

- 80% of Mixture B means $0.8\times 60=48$ liters are used. Thus, 20 liters of water and 28 liters of milk are mixed from B.

- Mixture C is being made combining the above mixtures, leading to 100 liters of water and 48 liters of milk.

- The ratio of milk to water in Mixture C is 48:100, which simplifies to 12:25.

Correct Answer: ? Option: 4, 12:25