Which of these is not a high level Linux package manager?

Which of these is not a high level Linux package manager?

• aptitude
• yum
• zypper
• linupdate

EXPLANATION

linupdate is the false one here. The others are all legitimate Linux package managers. Even though these are package managers, they use lower level tools to actually install the packages, such as rpm or dpkg.
Overview: http://www.tecmint.com/linux-package-management/
RPM & DPKG reference: http://packman.linux.is/