But no person who was on January 1, 1866 or at anytime prior there too entitled to vote under any form of government or who at that time resided in some In some foreign nation and no lineal Descendent of such person shall be denied the right to register to vote because of his inability to read and write sections of constitution

Question, which voting did the Supreme Court Decision address
A) Grandfather calls
B) Poll tax
C) Literacy test
D) Jim Crow laws