BEST list of candidate interaction diagrams to support the use case

[Jayadev Pulaparty]

49. Use case : Purchase Ticket Actors : Customer Preconditions: The customer is logged onto the systeem. The customer profile already exists. Postconditions: The ticket is sold and the seats are assigned to the customer and the system is updated. Primary Flow : 1. The use case begins when the customer selects the option to view flight information. 2. The system prompts for the departure and destination cities and the departure and return dates. 3. The user enters the departure and destination city, departure date, and return date. 4. The system displays a list of available flights, including the fare. 5. The user selects the flight they would like to reserve. 6. The system displays all available fare options for that flight. 7. The user selects the fare option they would like to reserve. 8. The system displays the fare that the user will pay. 9. The user confirms the rate. 10. The system pormpts for a credit card type, number, name and expiration date. 11. The user enters the card type, number,name, and expiration date. 12. The system submits the credit purchase. 13. The system reserves a seat on the plane for the user. 14. The system generates and displays a confirmation code to the user. 15. The user confirms receipt of the code. 16. The use case ends. Which of the following is the BEST list of candidate interaction diagrams to support the use case?

select departure and destination cities and departure and return dates, select flight, confirm the rate, enter credit information, seat is reserved, confirmation number is generated and the confirmation is displayed
select departure and destination cities and departure and return dates, select flight, confirm the rate, enter credit information, seat is reserved
select flight, confirm the rate, enter credit information, seat is reserved, confirmation number is generated and the confirmation is displayed
select departure and destination cities and departure and return dates, select flight, confirm the rate, enter credit information, seat is reserved, confirmation number is generated and the confirmation is displayed
I choose the 3rd option. Why should we be very specific like
select departure and destination cities and departure and return dates whereas "select flight" interaction diagram should capture the same scenario at a higher level.