Concord reported the following results from the sale of 5000 units in May: sales $440000, variable costs $320000, fixed costs $90000, and net income $30000. Assume that Concord increases the selling price by 5% on June 1. How many units will have to be sold in June to maintain the same level of net income?

a) 4225.

b) 4766.

c) 4750.

d) 5000.