"People just had to hear it."
Translation:Das mussten die Leute einfach hören.
'Es' is more indefinite than 'das' in german. But since you can't tell that apart in the english sentence, both should be fine. 'Die Leute mussten das einfach hören' is correct, too. Basicly, the syntax is subject - verb - object or object - verb - subject. Here, you've got a compound verb which uses an auxilary which is placed instead of the verb while the actual verb moves to the end.
We don't get identical exercises. you might have seen this sentence in multiple choice type of exercise while someone else sees it in translate this to German type of exercise.
So when you have a question about multiple choice type of exercise you need to copy paste the sentences so others can see them.