I prefer the first.
If you want to use the second, I suggest commas before "who" and after "kind".
Student or Learner
I have a question.
"The policeman who stopped our car wasn't very kind" is the correct answer by book.
But I think "The policeman who wasn't very kind stopped our car" can be correct answer.
I want check it, but i don't have a teacher.
Can the second one be rewritten as 'The not-so-kind policeman stopped our car'?
It's difficult to tell without knowing the question, but my suspicion is that 2. is not a correct answer.
"Which policeman stopped your car?" can be answered by 2, but not 1.
"What was the policeman like who stopped your car?" can be answered by 1, but not 2.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.