select from:a vertical linea horizontal linean upward sloping straight linean upward sloping curve which is not a straight linea downward sloping straight linea downward sloping curve which is not a straight line

Orange and apple juice are perfect substitutes for Mingkai - he receives the same marginal utility from the glass of orange juice as from the glass of apple juice. Assume that the price of orange juice is $2, the price of apple juice is $3 and Mingkai's income is $18. a) Draw the income-consumption curve (put orange juice on the horizontal axis and the apple juice on the vertical axis). . This curve is [ Select ] b) Draw the price-consumption curve when the price of orange juice changes. . For values Qorange 6, this curve is [ Select ]