The correct answer is: A. a, an
A book is always an acceptable gift because it is a thoughtful and personal present that can be enjoyed by people of all ages. It is also a versatile gift that can be given for any occasion, from birthdays and holidays to graduations and weddings.
The article “a” is used before singular nouns that refer to a general or nonspecific item. In this case, the noun “book” is being used in a general sense to refer to any book, not a specific book.
The article “an” is used before singular nouns that begin with a vowel sound. In this case, the noun “book” begins with a consonant sound, so the article “a” is used.
The article “the” is used before singular nouns that refer to a specific item. In this case, the noun “book” is not being used in a specific sense, so the article “the” is not used.