A school has 250 pupils. 3/5 of the pupils are boys. 2/15 of the boys and 1/25 of the girls are absent. How many pupils are absent?

The total number of pupils is 250, and $\frac{3}{5}$ of them are boys.

$$\text{Number of boys} = \frac{3}{5} \times 250 = 3 \times \frac{250}{5} = 3 \times 50 = 150$$

The rest of the pupils are girls.

$$\text{Number of girls} = \text{Total pupils} - \text{Number of boys} = 250 - 150 = 100$$

$\frac{2}{15}$ of the boys are absent.

$$\text{Absent boys} = \frac{2}{15} \times 150 = 2 \times \frac{150}{15} = 2 \times 10 = 20$$

$\frac{1}{25}$ of the girls are absent.

$$\text{Absent girls} = \frac{1}{25} \times 100 = 4$$

Add the number of absent boys and absent girls.

$$\text{Total absent pupils} = \text{Absent boys} + \text{Absent girls} = 20 + 4 = 24$$

The total number of absent pupils is 24.

The correct option is C.
The final answer is $\boxed{\text{24}}$.