Answer: 1.
- A 0
- B n
- C 1
- D n!
Correct answer: C. 1
Explanation: nC<sub>0</sub> = n!/(0! × n!) = 1. There is exactly one way to choose nothing.
Counting tree for selecting 2 items from {A, B, C} without repetition: 3 x 2 = 6 ordered arrangements.
Concept context
Counting, arrangements, and selections