How long has this sandwich been in here?

Which of these situations would be the best use of BitLocker?

A) You need to prevent access to a spreadsheet in the public shared folder

B) You have a USB flash drive that needs to be unreadable by others

C) You need to copy an encrypted presentation onto a DVD-ROM with other non-encrypted files

D) You need to create a series of hidden shares for a top-secret project

E) You need somewhere to keep your lunch during work hours