Which normal form is considered adequate for normal relational database design?

Consider the following database relations containing the attributes
Book–id
Subject–Category–of–book
Name–of–Author
Nationality–of–Author
With book–id as the primary key.
(a) What is the highest normal form satisfied by this relation?

(b) Suppose the attributes Book–title and Author–address are added to the relation, and the primary key is changed to {Name–of–Author, Book–title}, what will be the highest normal form satisfied by the relation?

Consider the following database relations containing the attributes
Book–id
Subject–Category–of–book
Name–of–Author
Nationality–of–Author
With book–id as the primary key.
(a) What is the highest normal form satisfied by this relation?

(b) Suppose the attributes Book–title and Author–address are added to the relation, and the primary key is changed to {Name–of–Author, Book–title}, what will be the highest normal form satisfied by the relation?

Suppose we have a database consisting of the following three relations.

FREQUENTS (student, parlor) giving the parlors each student visits.

SERVES (parlor, ice-cream) indicating what kind of ice-creams each parlor serves.

LIKES (student, ice-cream) indicating what ice-creams each student likes.

(Assume that each student likes at least one ice-cream and frequents at least one parlor)

Express the following in SQL:
Print the students that frequent at least one parlor that serves some ice-cream that they like.