A simile is a comparison of one thing to another, for example "smart as a fox".
The only comparison to something else that I find in the lines above is "like the rusty latch" - and this is a simile. The correct answer is then a) .
The true meaning of the word "benign" in this sentence is - harmless. It is the word that originates from Latin word "benignus". In medical terms, it refers to something that does not cause death or serious injury. Also, it is most commonly used to describe tumors which are not cancerous. The famous American film director once said: "The most beautiful words in English are not 'I love you' but 'It-s benign'." This word can also be used to describe one's character, meaning that he or she is kind, gentle and that can hardly harm anyone.
