Final answer:
The correct answer is C. Poll tax, which was an annual tax that had to be paid in order to vote; it disproportionately affected African Americans and was eliminated as unconstitutional.
Step-by-step explanation:
The voter suppression method that required two consecutive years of on-time payments for someone to have the right to vote was C. Poll tax. This was an annual tax that had to be paid in order to register to vote. The poll tax was cumulative in several states, meaning that if a person decided to vote, they would need to pay not only the tax for that year but also for any unpaid poll taxes from previous years. The requirement disproportionately affected African Americans and was ultimately rendered unconstitutional.