In the consumer choice model, we assume consumer's preferences possess certain properties. a) List and define (in a sentence or two) the two properties satisfied by rational preferences. (2 points) b) Assume that a consumer's preferences are rational and well behaved; briefly describe why their indifference curves can't cross (feel free to use a graphical example in your explanation). (4 points) c) Define a diminishing marginal rate of substitution. Which preference property implies diminishing MRS (you do not need to explain your answer) ? (4 points)