Thanks Jerry. This my outcome. Just wondering why i have some extra lines. Or did you just leave them out?
theo@Lenovo-B50-30:~$ apt policy sudo
sudo:
Geïnstalleerd: 1.8.16-0ubuntu1.4
Kandidaat: 1.8.16-0ubuntu1.4
Versietabel:
*** 1.8.16-0ubuntu1.4 500
500 http://ftp.tudelft.nl/archive.ubuntu.com xenial-updates/main amd64 Packages
500 http://ftp.tudelft.nl/archive.ubuntu.com xenial-security/main amd64 Packages
100 /var/lib/dpkg/status
1.8.16-0ubuntu1 500
500 http://ftp.tudelft.nl/archive.ubuntu.com xenial/main amd64 Packages
theo@Lenovo-B50-30:~$