Why Was Voluntary Assumption of Risk Rejected as a Defence

Why was voluntary assumption of risk rejected as a defence by the Court of Appeal in Pitts v Hunt?

A) Because the claimant did not willingly accept the risk of injury
B) Because it was excluded by s 149 of the Road Traffic Act 1988
C) Because the courts considered that the case was better dealt with on the principles of illegality
D) Because the courts considered that the case was better dealt with on the principles of contributory negligence