Hello I found a probability problem but I don't know how to solve it. Could you give me some tips or courses where I could learn formulas or anything else that I need to know to be able to solve this problem please.

A certain area of the North Pole contains 10 polar bears, 12 reindeers, and 5 arctic foxes. From these animals, a group of 7 will be selected for Santa's new animal training program. How many distinct groups are possible if

a - there are no restrictions.

b- there are 2 polar bears, 3 reindeers, and 2 arctic foxes in the group

c - there are exactly 4 reindeers in the group

d - there are no polar bears in the group

e - there is at least one reindeer in the group

f - there are the same number of polar bears as reindeer in the group

2 - Nine reindeer are lined up for a photograph

a- How many different arrangements are possible?

b- How many arrangements are possible if Rudolf must be first and Proncer must be last ?

d- How many arrangements are possible if Rudolf, Dasher, Dancer, and Donner must be together ?