Plot the indifference curves for the following cases:

a) There are 2 formats of bottled water: 500 ml bottles (x) and 1 liter bottles (y) that can be represented as U(x , y) = 0.5x + y

b) There are 2 goods in the economy: controls (x) and batteries (y) whose indifference curve is U(x , y) = min{x, 4y}

c) Suppose that Enzo considers that drinking Coca-Cola is bad for him, but drinking water is very beneficial for his health. Plot the indifference curves.

d) Miguel likes notebooks and is neutral with respect to pencils (no matter how many pencils he has). Plot how each of the preferences would look like.