All of these were used in the south to promote segregation and limit the rights of blacks except? poll taxesjim crow lawsliteracy testscrop subsidies

Poll taxes means you have to pay a tax before allowed to vote.  That's a way of preventing poor persons (like blacks in the South) from voting.

Literacy tests would require persons to pass certain standards of reading and writing in order to qualify for voting.  Again, such methods were aimed at blacks, who had not had access to the same education as whites.

Jim Crow laws were all sorts of segregation laws aimed at keeping blacks in "their place" and away from places where white society did not want them to be.

All such measures were used to promote segregation and limit the rights of blacks.  So the answer that doesn't fit is "crop subsidies," which would be payments made to assist farmers.