Answer:
a. to avoid loss of documents
b.graduate documents, certificate
A comma and a conjunction always work well but it really depends on the sentences you are combining.
The topic that would attract readers the most would be B, so that one is the most appropriate answer.
Answer:
Mark Twain created his characters based off of real people in his life.
Explanation:
He uses people from both his adulthood and childhood in his works.
Hope this helped :)