If 50 students each received 15 oranges, how many oranges would each student receive if the same total number of oranges were shared among 30 students?

The oranges were initially shared among 50 students, and each student received 15 oranges.

$$\text{Total oranges} = \text{Number of students} \times \text{Oranges per student}$$ $$\text{Total oranges} = 50 \times 15$$ $$\text{Total oranges} = 750$$

Now, the 750 oranges are shared equally among 30 students.

$$\text{Oranges per student} = \frac{\text{Total oranges}}{\text{New number of students}}$$ $$\text{Oranges per student} = \frac{750}{30}$$ $$\text{Oranges per student} = 25$$

Each student will get 25 oranges.

The correct option is C.
The final answer is $\boxed{\text{C. 25}}$.