Why Was a Duty of Care Found in the Police

Why was a duty of care found in the police case Swinney v Chief Constable of Northumbria Police [1997]?

A) Because it was not about the police's investigation of crime but about their other operations
B) Because Swinney had the requisite degree of proximity to the police while the claimants in e.g. Hill v Chief Constable of West Yorkshire [1989], Osman v Ferguson [1993], Brooks v Commissioner of Police for the Metropolis [2005] or Smith v Chief Constable of Sussex Police [2008] did not
C) Public policy considerations dictated that a duty should be owed