True indeed yes of course you are absouletly correct
The correct answer is A.
The author does not allude the visitor as being Herbert. He merely call it "the thing outside". Therefore, this is not a way the author creates suspense in the story.
The rest of the options: the description of the scraping, the echoes of the knocks, and the difficulty to find the object that was needed, are all elements that help build up suspense in this passage.
The problems you see: is where is says “won’t eat nothing accept” when it should be “won’t eat anything accept”
ALSO it should be spelled leaves, not leafs.