Question

Supporters claim that closed primaries make candidates more responsive to _____.

Answer 1

Supporters claim that closed primaries make candidates more responsive to _____THE VOTERS.                     

Answer 2

I believe the answer is: The voters

In a closed primary, the voters need to make a declaration of their party affiliation before they are allowed to vote. This mean that candidates that are chosen in a closed primary is more likely to have similar point of view/principles with the voters, and make it easier for them to respond to the voters.