According to Gernsbacher's (1997) Structure Building Framework, Which Sentence of a Paragraph

According to Gernsbacher's (1997) Structure Building Framework, which sentence of a paragraph do people usually read most slowly, and why?

A) the first, because they are laying a foundation for the ideas that follow
B) the last, because they are integrating the meanings of the individual statements
C) the first, because they are adjusting their comprehension to the difficulty-level and style of the author
D) the last because it summarizes information in the preceding sentences