Nancy Lerner is taking a course from Professor Goodheart who will count only her best midterm grade and from Professor Stern who will count only her worst midterm grade. In one of her classes, Nancy has scores of 50 on her first midterm and 45 on her second midterm. When the first midterm score is measured on the horizontal axis and her second midterm score on the vertical, her indifference curve has a slope of zero at the point (50,45). This class could...

a. be Professor Goodheart's but could not be Professor Stern's

b. be Professor Stern's but could not be Professor Goodheart's

c. be either Professor Goodheart's or Professor Stern's

d. There is not enough information to tell whose class it could or couldn't be

In this exercise, you should consider the indifference curve which refers to the curve that represents the preferences of an individual. The slope curve is known as Marginal Rate of Substitution (MRS). An indifference curve of normal goods is downward sloping and convex to the origin.

When the indifference curve has a slope equal to zero, the marginal rate of substitution is equal to zero as well. When Nancy scores 30 marks in each of the subject, the marginal rate of substitution is zero. In this case, she marks 50 in one of the subject, which must belong to Professor Goodheart as he counts Nancy´s best midterm grade.