I have a problem with this question, could you help me to solve it? Step by step

1. Consider 12 books of three different authors: 3 books of the first author, 4 of the second and 5 of the third author. In how many ways can these books be ordered on a shelf if a. [1 pt.] There are no restrictions. b. [2 pt.] Books of the third author must be placed on the right-hand side of the shelf, and the authors of the first seven books on the shelf must alternate. c. [1 pt.] Books of the same author must be placed together. d. [2 pt.] In how many ways can these 12 books be divided among 4 children, such that they get 3 books each