4. Suppose the monopolist whose data are shown to the right is able to practice 1^st degree (perfect) price discrimination. In this case the total number of units sold and the price of the last unit sold will be:

price of last unit = 6, total quantity sold = 6.
price of last unit = 3, total quantity sold = 5.
price of last unit = 10, total quantity sold = 5.
price of last unit = 7, total quantity sold = 8.
price of last unit = 8, total quantity sold = 7.