Which BEST describes this sentence from paragraph 2?

The CN Tower in Toronto, Canada, held that title until 2008, when the Burj Dubai eclipsed it.
A) It is the main idea of this essay and supported by all other paragraphs.
B) It is the main idea of paragraph 2 and a major detail of the essay.
C) It is a major detail of paragraph 2.
D) It is a minor detail of paragraph 2.