Option B is the best choice. Acid from the book end papers and glue will migrate to the letter and destroy it, if left as it is. The removal should be left to a professional and both letters deacidified and then stored flat in an archival folder or sleeve and kept with the book, which has an obvious --if not critical-- association with the letters. Do not seal the letters in a sleeve or laminate them. Never do that to any document --the basic rule in paper conservation is never to do anything that cannot be easily undone without damage. Kevin Mac Donnell Austin TX