Answer:
B. The authors include details about the changes in diets over time to inform readers about how sugar has transformed what we eat.
Explanation:
i took the test on edge 
(btw ur really pretty)
 
        
             
        
        
        
The answer is: a noun. 
A noun is a word that names a particular thing or a set of things. Nouns are classified in many ways, but for clarity purposes, it can be said that the two more general forms of the noun are the proper noun (which refers to unique entities, like Europe or John) and the common noun (which refers to a class of entities, like neighborhood or country).