Question: Clean scale of the inside of a tea kettle.

  Options: 
 A. Place a mixture of 50 percent vinegar and 50 percent water into the kettle. Switch it on and let it boil. Cool, the remove the mixture. Give the inside a wipe with a cloth, rinse and done.
 B. Place a mixture of 90 percent water and 10 percent alcohol into the kettle. Switch it on and let it boil. Cool, the remove the mixture. Give the inside a wipe with a cloth, rinse and done.
Answer: A