1. a List the 24 different orders in which four people A, B, C, and D may sit in a row.
2. b Determine the probability that when the four people sit at random in a row:
- i A sits on one of the end seats
- ii B sits on one of the two middle seats
- iii A and B are seated together
- iv A, B, and C are seated together, not necessarily in that order.