My best bet would to go with 'were' because they sound similar and it just seems more professional.
Answer:
Armed conflict escalated in August 2017 in Rakhine State, causing Rohingya to flee to nearby Bangladesh.
Explanation:
1.) who
2.) why
3.) whose
4.) what, how
5.) that
6.) why
7.) whether
8.) when
9.) what
I hope you can use words over again in this case. Let me know if you need explanations!