Suppose Summerland can produce either 60 units of good A or 120 units of good B, and Peachland can produce either 200 units of good A or 200 units of good B. For them both to benefit from trade, how much will each unit of A exchange for? a. 0 units of B since only if the good A is free will there be mutual benefit b. between 0.5 of a unit and 1 unit of B c. more than 1 unit of B d. between 1 and 2 units of B