The correct option is
B the/no article/the
OPTION "B" is the correct answer.
EXPLANATION:
There are two types of articles:
DEFINITE ARTICLE (THE) : Article 'the' is used to refer to a DEFINITE thing or person.
INDEFINITE ARTICLE(A/AN): Article 'a/an' is used to refer to a thing or person in general. For instance: man, door etc.
Article 'a' is used with consonant sounds whereas article 'an' is used with vowel sounds.
In the first blank, article "the" will be used because article 'the' is used when one talks about a specific thing or person. here, a specific book is being referred to.
In the second blank, "no article" will be used because "no article" is used before "noun + number" ( page + 20).
.In the third blank, article "the" will be used because article "the" is used when one talks about a specific thing or person, Here, the specific text on the page is being referred to.