Final answer:
White primaries and grandfather clauses were used as electoral strategies to get around the 15th Amendment and eliminate black influence on elections.
Step-by-step explanation:
The electoral strategy that was used to get around the 15th Amendment and effectively eliminate black influence on elections by affecting how candidates were selected to run include:
White primaries: These were primary elections in which only white people were allowed to vote. The state party organizations argued that as private groups, they had no obligation to follow the Fifteenth Amendment's requirement not to deny the right to vote on the basis of race.
Grandfather clauses: These exempted whites from voting requirements if their ancestors had voted prior to the Fifteenth Amendment's enactment.
Poll tax was not used as an electoral strategy to get around the 15th Amendment. It was an annual tax imposed in some states before a person was allowed to vote, which disproportionately affected African Americans and other marginalized groups.