Just a small suggestion to help you in future if you appear for ielts or any related exams.For me actually i wrote it (rope) .
and i was sure it is not (ropes) until i saw some guys here answered it as (ropes)
Always try to check entire sentence after substituting your answer in space provided to check for grammatical errors. If sentence demands plural go for words with plural forms or singular. This can help you to avoid silly mistakes and lose scores. Hope this helps!