The Idea That Open or Top-Two Primaries Yield More Moderate

 The idea that open or top-two primaries yield more moderate candidates than closed primaries 

A)  explains why most states stopped using such primaries in the past decade. 
B)  explains why most states prefer such primaries. 
C)  has not been supported by research. 
D)  explains why party leaders prefer such primaries. 
E)  explains why party leaders are hesitant to use such primaries.