(2) the failure by the holder to take appropriate measures to prevent, in the premises concerned,(a) the unlawful possession, consumption, sale, exchange or giving, in any manner, of a drug, narcotic or any other substance that may be held to be a drug or narcotic;
(b) the unlawful possession of a firearm or any other offensive weapon;
(c) acts of violence, including theft or mischief, that may disturb the peace of occupants or customers or of residents of the neighbourhood.