Students generally have more difficulties with informational text than with narrative text. Several ...

Students generally have more difficulties with informational text than with narrative text. Several reasons for this are listed here. Which is not a reason?
 
Some text structure is unique to informational text, therefore, reading exposition may require some processes not used with narrative text.
 
Informational text is characterized by low density.
 
Students often have less background knowledge to bring to informational text because the text may present complex and unfamiliar ideas.
 
There may be more specialized vocabulary in informational text not in the oral language of the reader but necessary for understanding the material.