In a 56 liters mixture of milk and water, the ratio of milk to water is 5 : 2. In order to make the ratio of milk to water  7 : 2, some quantity of milk is to be added to the mixture. The quantity of the milk present in the new mixture will be:

Given,

Ratio of milk and water in a 56 liters of mixture = 5 : 2

$$=$$>  Quantity of milk in 56 liters mixture = $$\frac{5}{5+2}\times56=40$$

$$=$$>  Quantity of water in 56 liters mixture = $$\frac{2}{5+2}\times56=16$$

Let the quantity of milk added to make the mixture in the ratio  7 : 2 = $$a$$

$$=$$>  $$\frac{40+a}{16}=\frac{7}{2}$$

$$=$$>  $$40+a=56$$

$$=$$>  $$a=16$$

$$\therefore\ $$Quantity of milk present in new mixture = 40+a = 40+16 = 56 liters

Hence, the correct answer is Option D