You are expecting a very important file from a co-worker in a remote office to be sent to you through e-
mail. You finally call the co-worker and tell him that you have not received the file. He informs you that he
sent the file yesterday, but will send it again immediately. After some time, you still have not received his e-
mail message. You contact the Technical Support department and ask them for help. After some
investigation, Technical Support finds the e-mail from your coworker with an attachment named
salesnumbers.exe in the spam folder of your e-mail client.
What is the most likely reason that the e-mail message was filtered out?