Answer:
He believed the Catholic Church got it wrong on salvation
This was (and, for many, remains) the defining difference between Protestants and Catholics. ... Luther believed people were saved by faith alone and that this was the summary of all Christian doctrine, and that the Catholic Church of his day had got this wrong
13 is the 3rd one
17 is the 2nd one
18is the 3rd one
24 is the 3rd one.
Hope this helps!
3 7 and 4 also 5 it makes sense