Which of the following statements best describes mountains and hills? a. “hill” and “mountain” mean the same thing. b. whether a landform is a hill or mountain is subjective; one person might call a certain landform a hill, and someone else might call it a mountain. c. a hill is defined as a rise that is less than 1,000 feet, and a mountain is anything over 1,000 feet. d. a mountain is defined as any rise over 5,000 feet, and any rise below that elevation is called a hill.