Answer:
Schooling is hard for some students.
Explanation:
Option 1: The end of the school year is irrelevant to the sentence. Incorrect.
Option 2: Schooling isn't hard for every student, some is a good word to describe 'not all'. Changing school to Schooling is a good noun phrase to use, during 'schooling' times it's hard for some students. Correct.
Option 3: Teachers are irrelevant to the sentence. Incorrect.
Option 4: The end of the school year is irrelevant to the sentence. Incorrect.
