Wht are most of the members of ocpe located?

The sun's parallax would be 180 degrees, greater than which you can't get.  so a. would be your anwser 

This would be an open primary. a closed primary people can vote only prior to election day if the party if they are registered. independent voters can not participate. there is not a wide-open primary, but there is a semi-open primary.

The answer is a for sure