To find the total number of students attending McCord Middle School, we can set up the equation based on the information provided.
We know that 200 students represent 40% of the total student body. Let the total number of students be \( x \).
We can express this relationship with the equation: \[ 0.4x = 200 \]
To find \( x \), we can solve for it by dividing both sides by 0.4: \[ x = \frac{200}{0.4} \] \[ x = 500 \]
Therefore, the total number of students attending McCord Middle School is 500 students.
The correct response is: 500 students.