RBS vs Risk Breakdown Structure

 OK. I had this question on a practice test.  
Which of the following represents a hierarchically organized depiction of resources to be used on a project?
A. OBS
B. BOM
C. RBS
D. None of the choices are correct
E. WBS

I thought the answer is D because it would be a Resource Breakdown Structure but the practice test said it was C. RBS.  I thought RBS was Risk Breakdown Structure?  I am confused.   

RBS is also Resource Breakdown Structure. Output of Estimate Activity Resources

 Dont follow old stuff. 

check the relevancy with current/ applicable pmbok version.

5 options questions are old, based on old version, will confuse you, misguide you.

always check and follow material - based on 4th edition  or for new 5th edition or the date of modification of material .