Which of the following does NOT need to be established for an auditor to be found guilty of negligence?

a$.$

There was a contractual relationship between the auditor and the plaintiff.

b$.$

A breach of the duty of care $($negligent conduct$)$ occurred.

c$.$

There was a causal relationship between the breach of the duty of care by the auditor and the loss that was suffered by the plaintiff.

d$.$

The auditor had a duty of care to the plaintiff.