Explain how the poll tax and literacy tests were not a violation of the 15th amendment

In theory, all people had the right to vote regardless of race in states where voting restrictions were in place. One could go and vote, but had to complete the require state-mandated steps to do so. Technically, the poll tax and literacy tests were to be administered to all voters. However, the corruption of this often occurred at the polls where whites would "pass" the literacy tests where blacks could not even if they did. White workers would "forget" to charge the poll tax to whites or charge less so they could vote. Some states initially had a grandfather clause that stated if you grandfather could vote before the Civil War then you were exempt from the poll taxes and/or literacy test. This was a given for almost all whites and an immediately made all blacks qualify for the mandates because blacks did not have the right to vote prior to the Civil War. 

The answer is c. religion