What is the test for determining whether a defendant has a duty to act reasonably?

2 It is this type of duty analysis which causes the most confusion. Absent external policy considerations, everyone has a "duty" to act reasonably. (See Rowland v. Christian, supra, 69 Cal.2d at p. 112, 70 Cal.Rptr. 97, 443 P.2d 561.) The scope of that duty is defined by the reasonable person standard. When a defendant has failed to take precautions against a risk of injury which was not reasonably forseeable, he has not acted unreasonably, i.e., he was not negligent. Thus, where forseeability of risk is the issue, the question is not whether a duty existed but rather whether an admitted duty has been breached or, more simply, whether the defendant was negligent.