According to the 2014 AAPC Survey, it shows coders' salaries rose 2 percent to an average of $50,030 for credentialed professional coders.
The clue is in the phrase "coders' salaries rose 2 percent to an average of $50,030 for credentialed professional coders."
This implies that the information was gathered from a large group of coders, which is characteristic of a survey.
Here's why the other options are not as likely:
Study: This could be a more thorough examination of a particular aspect of coding salaries, but it wouldn't necessarily involve surveying a large group of coders.
Report: This could be a summary of the findings of a survey or another type of research, but it wouldn't be the primary source of data.
Analysis: This could be a deeper look at the data from the survey, but it wouldn't be the primary source of information.
Review: This could be an evaluation of the survey methodology or findings, but it wouldn't be the primary source of data.