The novel was so captivating that I couldn’t put it ___.

Correct Answer: B. Down

The phrase “couldn’t put it down” is an idiom often used to express how engaging or captivating something is, especially in the context of a book or novel. When someone says they “couldn’t put it down,” it means the material was so interesting or compelling that they were unwilling to stop reading or viewing it.
In the given sentence, the missing word is the direction or location where the person couldn’t put the novel. The correct choice is “B. Down,” as in “I couldn’t put it down.” This phrase implies that the individual was so engrossed in the novel that they didn’t want to stop reading it, emphasizing the captivating nature of the story.