4 because it doesn't relate to the other 3 answers
A participle has the following form: verb + -ing, and the only word in this sentence that takes that form is A, 'flying', which is the correct answer.
If this were a question on my test, I'd probably go for tolerant or sentimental. I'd probably go for sentimental, because if the sentence had a more tolerant tone, it would say something like "My car isn't the greatest, but I can live with it".
Answer:
"But a subgroup of kids, about 10% or 20%, showed a dramatic onset of symptoms after their injury and persistent symptoms that in some cases remained even 12 months after the injury."
Explanation:
I read the Article and took the quiz. I really hope this help :D