Answer: 1.
- A 0
- B 1
- C Undefined
- D Infinity
Correct answer: B. 1
Explanation: By convention, 0! = 1. This makes combinatorial formulas work correctly.
Counting tree for selecting 2 items from {A, B, C} without repetition: 3 x 2 = 6 ordered arrangements.
Concept context
Counting, arrangements, and selections