Why Is There Less Data About What Influences the Decisions

Why is there less data about what influences the decisions of primary voters?

A) There is a perception of bias,as primary voters also vote on Election Day.
B) Partisan strength is not considered an important issue in primary elections.
C) Primary voters are less likely to participate in polls.
D) The smaller sample makes primary voting data less credible.
E) Primary voters have lower levels of partisan direction.