Step 1: Understanding Bentham's Hedonistic Calculus.
Bentham's Hedonistic Calculus is a method for calculating the amount of pleasure or pain produced by an action, considering multiple factors:
- A. Duration: The length of time that pleasure or pain lasts.
- B. Fecundity: The ability of an action to lead to further pleasures or pains.
- C. Purity: The extent to which an action leads only to pleasure without accompanying pain.
- D. Mortality: The chance that the pleasure or pain will result in death.
Step 2: Conclusion.
All of the factors listed—Duration, Fecundity, Purity, and Mortality—are parts of Bentham's Hedonistic Calculus.
Final Answer:
\[
\boxed{\text{The correct answer is 3. A, B, C and D.}}
\]