You don't ask whether D owed P a duty; you ask what duty D owes. Absent special circumstances (such as if D is a professional, or a child), D always owes P a duty of reasonable care. No matter what, 100% of the time. If you're watering your lawn, you owe people a duty of reasonable care. If you're working with a chainsaw, you owe people a duty of reasonable care. I must have used the word reasonable easily 50 times on my Torts exam (A+).
For the record, this strategy would have doomed anyone who took my torts exam. I guess my prof just had a lot more emphasis on those "special circumstances" where there is a heightened or lowered duty (for us, there were 5 levels of duty ranging from no duty to strict liability. We spent half the semester on this concept and had to know it all). So.. be sure to account for the way your professor taught the class.