(b) That's wrong. Although in the past there was some debate about questions of this kind, it is now clearly established that, if the essential elements of a particular cause of action can be satisfied on the facts of the case, there is no reason to debar a plaintiff from choosing to bring a legal action on the basis of one legal right rather than another.
On the facts of the case study, it is clear that the parties have a contractual relationship. The facts of the case study may also satisfy the essential elements of the tort of Negligence. In particular, a contractual relationship is one of the relationships which the courts have recognised as potentially giving rise to a duty of care. For the purposes of this question, it is not necessary to decide if the elements of the tort of Negligence are actually satisfied. We can simply say that, provided the elements of liability in tort law can be satisfied, then Miles would be entitled to bring an action in tort law, rather than in contract law.