To summarize that passage, which is an excerpt from frankenstein, basically the narrator stormed out, and locked their workspace away. Seeing the horrific reality that his creation could bring and thinking of all the possibilities that could go wrong by creating a female version of this "monster" caused him to decide that he should not fulfill his promise to his creation, to make HER. He went to his room to be alone, so as to not have the creature talk him into keeping the wretched promise, or even try to save him from the despair and sadness that he feels by charm, attempting to convince him to keep the promise. As he sits, lost in his thoughts, inspiration drains away still, leaving only gloom.
The reason for all this drama was the monster that the narrator felt he had created. He tore apart his work in his despair. Now, he sits, discouraged by both his failure and his monstrous reaction. Overall, this passage seems to talk about being alone, but it is really referring to a moment where the narrator let his fears drive him to be destructive, showing his inner monster. Hope this helps!
Answer: B. isolation from the world