14.04 - How do I remove virtualbox.list from etc/apt/sources.list.d/virtualbox.list

I am trying to update software of my Ubuntu 14.04 but there is an error:

malformed line /etc/apt/sources.list.d/virtualbox.list (dist) ; access to this source denied.
E:opening etc/apt/sources.list.d/virtualbox.list-ifstream::ifstream(13: Permission denied)
E: List of source could not be read
E:The package lists or status file could not be parsed or opened.

Could you please help me to remove this virtualbox.list.

I really appreciate yourhelp.