Answer:
b. An ordinary, prudent, and reasonable person under similar circumstances.
Explanation:
Negligence is a legal theory , which holds the defendant responsible for harm caused to the plaintiff.
These contracts include : a legal 'duty' of care 'breached' by defendant, where defendant's action are 'causation' to plaintiff 'damage'
Eg : Car Accidents, 'slip & fall' injury cases are usual examples of these.
So, the defendant has duty to act like 'A specialist trained in the area of the accident' - to make his careful duty prevent plaintiff from damage.