Save Your File with .RTF

My Lecturer informs me and always command us as his student to save and send our task by .RTF format. Why? Let me Show some advantage using .RTF extension.
  1. It can opened in any office software, such as: MsWord, OpenOffice
  2. It doesn't easy broken by virus

This format is seldom used so the virus maker couldn't broke the authentication of it's format. So start using this format guys.