Answer:
The answer is 2.
Step-by-step explanation:
In the question te ask you to replace the word, or pronoun "it" e.g in number 1 change "it" to "the story", 2 change "it" to "a great book", 3 change "it" to "people", 4 change "it" to "a good adventure".
Number 1 cannot work because mentioning the word "story" twice in sentence [B] does not make the story clearer or "clearest".
Number 3 also cannot work because changing "you" in sentence [E] to "people" does not change the meaning of the sentence.
Finaly number 4 reapeting "a good adventure" will not make sense in sentence [E].
I hope this answers your question.