Which of the Following Best Explains Why the White Primary

Which of the following best explains why the white primary was effective in accomplishing its goal?​

A) ​In the South, the poll tax was so high for primary elections that it was difficult to vote for those with very low incomes.
B) ​In the South, the Democratic primary election functioned like a general election as the Democratic Party was the predominant political force.
C) ​In the South, disenfranchisement was a direct and clear method of violating a constitutional amendment.
D) ​Literacy tests served to force voters to learn about candidates before they would be permitted to vote in the South.