If a person is risk averse, then she has a. diminishing marginal utility of wealth, implying that her utility function gets flatter as wealth increases. b. diminishing marginal utility of wealth, implying that her utility function gets steeper as wealth increases. c. increasing marginal utility of wealth, implying that her utility function gets flatter as wealth increases. d. increasing marginal utility of wealth, implying that her utility function gets steeper as wealth increases.