Let the number of seats in band be \( x \). Then the number of seats in choir will be \( 4x \) since there are four times as many seats in choir as in band.
The total number of students is given as 250, so we can set up the equation:
\[ x + 4x = 250 \]
Simplifying this gives:
\[ 5x = 250 \]
Now, divide both sides by 5:
\[ x = \frac{250}{5} = 50 \]
Thus, the number of students who can choose band is \( 50 \).
Therefore, the answer is 50 students.