Q: A: Sarah and Maria made a telephone using two cans and a string. It was a very long string. Maria went upstairs in her house and Sarah stayed downstairs. Maria spoke softly into the can. "I can hear you!' Sarah said back. How can this happen? A) Sound waves travel through a vacuum. B) Sound waves travel from high to low. C) Sound waves travel through solids like the string. D) Maria talked so loudly that Sarah could hear her without the phone.