Question: Stop a key from sticking in a lock, or from being difficult to put into a lock.

  Options: 
 A. Use a paper towel and apply some glue to the key. Wipe the key almost clean, a small amount of glue will be left behind allowing the key to slide in and out easily.
 B. Use a paper towel and apply some oil to the key. Wipe the key almost clean, a small amount of oil will be left behind allowing the key to slide in and out easily.
Answer: B