The correct answer is B) This building has been painted by student volunteers.
The other options are in the active (A and C), or in the imperative (D).
I would say that it depends on the audience. Personally, a debate regarding ethics and moral dilemma is interesting. Read The Fat Man and the Impending Doom. It's just one paragraph so it's not going to bore audience.
https://thedailydilemma.wordpress.com/2007/06/18/fat-man/
I believe that this type is a lecture-forum discussion.
The subject is Miss williams
I would say C because this passage talks about green building and how it's beneficial. Sentence 4 mentions about what the green roofs are made of and I don't think that would be necessary to include in this passage.