How do the first paragraphs of the essay relate to the concept of darkness included in the title of the essay

Which statement best explains the function of the subtitlein this text? a.it provides additional information that narrows the focusof the text.b.it draws attention to important information in the table ofcontents.c.it introduces the various sections that appear withineach chapter.d.it explains the author's primary reason for writing aboutthis topic.correct (a)