Suppose the marginal cost to produce a good is $10. There is only one person who is willing to purchase the good, and she is willing to pay $90 for one unit. According to the particular two-part pricing scheme from Lecture 3, an access price will be charged and then a per-unit price equal to the marginal cost, in this case $10. If we charge our consumer $10 per unit, how much could we charge her for access?