Slinking !! since slinking means to move slowly and carefully with gliding steps !!
I'm wondering if the sentence has a typo or it is really written as: The most amazing vacations are <u>to</u> places with...
Most sentences don't have that "to" in that part of the sentence or have it at all.
If that is the problem, then it looks like your question can be answered!
Answer:
A long way down
Explanation:
A steep cliff has to be very high, therefore, there is a long way down. You can also eliminate the other answers. Hope this helps. Ask any additional questions if you want :)