Supporters claim that closed primaries make candidates more responsive to

a. corporations

b. political parties

c. small businesses

d. voters

The closed primates make candidates more responsive to voters.

Explanation:

In closed primaries, candidates are in favor of voters.

In case of closed primaries, only the registered voters of the party participates and votes for the candidate while the candidate with higher number of votes participates in the election.

In case of open primaries, people do participate and vote for their desired candidate and this does not require a person to be registered with a political party.

Hence, the closed primaries make the candidate more responsive to voters as he/she would have to be with the views that are in line with the voters which could only make him/her the candidate with highest number of voters.