Hello. You forgot to mention that this question is about the article "9/11/2001" by Mike Kubic. Also, you forgot to mention that part A, shows that the word "haunt" as used in the 20th paragraph, refers to a place where a specific group of people is concentrated.
Answer:
A “proved to have deep roots”
Step-by-step explanation:
In paragraph 20 of the article, we can see that despite the campaigns and efforts of different countries to combat and eliminate terrorist attacks provoked by radical Islamist groups, these groups have survived, huddled in the Middle East. This shows how these groups have deep roots, being able to establish themselves strongly in one place, which shows the difficulty in controlling and decimating this threat everywhere on the planet.