Question

Fill in the blank with the plural form of the noun in the brackets.
That library holds thousands of (book) -----.
a. book
b. books
c. bookses
d. book’s

Answer 1

Hint: Nouns can be singular or plural based on the number of nouns taken into consideration. In the case of most regular plural nouns, we need to add ‘s’ to it. (Singular noun + S). Some examples for regular nouns are pens, bosses, thieves, chefs, wives, pennies and so on. There are different formats followed by various sets of regular nouns, for instance, some regular words require “s” at the end, while some take up “es” for those which end in “s, x, z, o, ch or sh”. Some words which end with “o”, take up ‘s’ at the end. Some regular words such as wife, life, knife, require “ves” to replace “f”.
Here, the word books is a regular noun which requires an addition of "s" at the end.

Complete answer:
Considering the above options,
a. Book: is a singular noun and hence is not the answer since the sentence refers to numerous books rather than a single book.
b. Books: since book is a regular noun, its plural form would be books, hence, this option is correct.
c. There isn’t a word such as bookses.
d. Book’s: we are not referring to how or what type of book it is, we are talking about the quantity. So, this is wrong in this situation.
Hence, Option b is the correct answer to the given question.

Note:
The only option in which one can get confused is, book's, but it is wrong. The word with the apostrophe which is entailed by an "s", is often used to tell something about the book.