Answer:
A) They hand copied written documents for their libraries.
Explanation:
Copying the books was considered one of the most useful activities for monks. The scriptorium and library became an indispensable part of the structure of the medieval monastery. There was even a saying: “Claustrum sine armario est quasi castrum sine armamentario” (“A monastery without a bookcase is like a fortress without an arsenal”). The monasteries kept the works of ancient authors, as well as textbooks on history, grammar, cosmography, medicine, astronomy, etc. The clergy began to rewrite the texts of scripture, the fathers of the church, and sometimes ancient authors, to which explanations and paraphrases were made.