16(1)(C)
When an information is withheld under 16(1)(c) it means there is some investigation going on, some information has been obtained which is confidential. In most cases it is the confidential information, the source of which cannot be disclosed since it is from an intelligence agency. 16(1)(c) states:
((c) information the disclosure of which could reasonably be expected to be injurious to the enforcement of any law of Canada or a province or the conduct of lawful investigations, including, without restricting the generality of the foregoing, any such information
(i) relating to the existence or nature of a particular investigation,
(ii) that would reveal the identity of a confidential source of information, or
(iii) that was obtained or prepared in the course of an investigation; or
It is only triggered when there is some sensitive information found which cannot be disclosed. If you have no criminal history, there is no need to worry. Sometimes false alarms are raised and the law enforcement has to conduct investigation. You can't do much about it. Your application will take a little longer than usual.
Source: Legalfalcon
http://www.canadavisa.com/canada-immigration-discussion-board/thank-you-legalfalcon-t408185.0.html