The donatist heresy was repudiated when the orthodox church declared that

select one:
a. jesus was of the same substance as god.
b. jesus was the son of a virgin.
c. the sacraments confer grace regardless of the spiritual state of the priest administering them.
d. any true believer may receive revelations from god.
e. all churches and sacred books must be destroyed.

The right answer is c.

Explanation:

By stating that the sacraments received their validity from God, not from man, Rome and Northern African Christian communities in communion with Rome stood in stark opposition to the top belief of the Donatists. The latter stated that the validity of sacraments depended on the worthiness of the minister, and if a priest did not enjoy divine grace, he could not administer the sacraments. The controversy started in the 4th century CE and in 412 and 414 severe laws were passed that deprived Donatists  from their civil and ecclesiastic rights. One of their major opponents was St. Augustine.

d. dr. francis collins