Answer:
B) They couldn“t vote if their grandfather had not been allowed to vote.
Step-by-step explanation:
Grandfather clauses are a provision in which an old rule continues to apply to some existing situations.
From 1895 to 1910 it was used by seven Southern States to deny African Americans to vote. The clause provided that those who have voted before 1866 or 1867 or their descendants, would be exempt for education, tax or property requirements to vote. On the year 1870 the fifteenth amendment was adopted, but since the African Americans who were slaves in those states did not fulfill the requirements of the grandfather clause they were supposed to pass restrictive voters registrations rules.
In 1915 the U.S. Supreme Court found the clauses unconstitutional because it violated the equal right of voting guaranteed by the mentioned amendment.
I hope this answer helps you.