Answer:
The meaning of curtailed in the sentence is:
B. restricted.
Step-by-step explanation:
To curtail means to reduce the quantity of something. However, even if we did not originally know that meaning, we could have guessed it through context clues.
The passage says that suspensions were curtailed. Later on, it says teachers need to administer alternative discipline practices. That means teachers have to find other ways to "punish" students. From that, we can conclude that curtail means B. restricted. The number of suspensions has been reduced, which forces teachers to spend more time looking for other ways to discipline students.