Dr. Loomis is interested in learning more about children who hurt and kill their families, so he pulls files from the sanitarium where Michael Myers was treated early on to gain more information. He is looking for something similar in these children's childhoods that could predict their later evildoings. Much of the data Dr. Loomis found were interviews with open-ended items and responses, so he needed to search through the documents looking for themes, grouping them, and then assigning them numbers so that he could analyze them. Dr. Loomis was _________ these survey items. 

Group of answer choices 

coding 

manipulating 

content analyzing 

none of these