A plane flight has been cancelled and the 28 passengers must be booked onto 4 alternate flights called flights A,B,C,D with each subject to the following restrictions:

i) Flight A has 12 empty seats but only 9 are available to passengers from the cancelled flight.

ii) Flight B has 8 empty seats, all available to passengers from the cancelled flight.

iii) Flight C has 14 empty seats, 5 of which are available to passengers from the canceled flight.

iv) Flight D has 9 empty seats, six of which are available to passengers from the canceled flight.

Passengers as well as seats are distinct

a.) How many different ways can passengers from the canceled flight be assigned seats on flight B?

b.) How many different ways can passengers from the canceled flight be assigned seats on flights A and B?

c.) How many ways can the passengers from the cancelled flight be assigned to flights A,B,C?

d.) How many ways can passengers from the canceled flight be assigned to flights A,B,C,D?