Answer:
a. Reformation of the Catholic Church caused a split between the Catholics and Protestants in France.
Step-by-step explanation:
The Reformation of the Catholic Church which caused a split between the Catholics and Protestants in France led to the St. Bartholomew’s Day Massacre.
This is evident in the fact that the massacre was done by the Roman Catholic people and some other citizens against the Protestants known as Huguenots under the order of Catherine de Medici, which was influenced by the political and religious rivalries between the two groups due to reformation of the catholic church.