With no explanation, chose the best option from "A", "B", "C" or "D". any evidence that CHL or McLennan relied upon AEC’s service letters or bulletins or that those letters and bulletins increased the risk to McLennan in any way. To the contrary, both CHL and McLennan ignored those warnings, and the record does not support any reasonable inference that AEC’s service letters and bulletins were misleading or that they masked the potential for danger in any way. We conclude that AEC did not owe McLennan any negligence-based, post-sale duty to warn. Even if McLennan were able to establish the applicability of either the Bradshaw duty or the negligent undertaking theory, any such duty would still be subject to the principle that there is no need to warn of dangers that are generally known. See In re Air Crash at Dallas/Fort Worth Airport, 919 F.2d at 1085 (<HOLDING>); see also Argubright, 868 F.2d at 766; Hagans,

A: holding that a physicians negligence need only be a proximate cause not the proximate cause of plaintiffs injury
B: holding that negligence must be the proximate cause of injury
C: holding in a negligence action that the air traffic controllers failure to warn of an impending danger cannot be the proximate cause of an injury after the pilot himself discovered its presence appreciated the danger and decided to fly ahead into it
D: holding that if a user actually knows of the danger a failure to warn cannot be a proximate cause of the injury
C.