Reading 47, Security Market Indices, EOC's correct, reading, question, first

mar350

Hi there!
Straight to my question:  In reading 47 (CFAI book 5) there were a few things about REITs.  In the EOC for this chapter, question 31:
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Please correct me if I’m wrong, but reading this question is the first time I’ve come across these indicies.  The correct answere is B.  Can someone please clarify why?  What are the other indicies?