<em>Personification has to with giving human attributes to non-human objects.</em> In this case, there is no such thing as a "physical heartbeat of the group." A group cannot have a heartbeat. However, figures of speech (personification is one of them) are helpful in order to effectively convey a message.
Personification helps send the reader a message that the activist group acts as one body. It lets the audience know that the activist group is united, acts as a solid community, and as one united front. Therefore, using personification creates a stronger tone that effectively conveys a message.
The main setting of the book is where the characters of the book are usually at. If they are at the park more than they are at home, then the main setting would be the park.
THe three minor characters are the characters that add the most to the story. If the book is in first person, then one of the main characters is the person talking. But the three people that are in the story most and talked about most are the three main characters.
Hope this helps :)
The option is (D).
It is obvious the first question would be what is the text about,what does the author try to convey and how does he presents the facts to manage his goals.