help a & b quick pls

Full Serve Inc. has a number of divisions. One division, Gamma, makes zippers that are used in the manufacture of boots. Another division, Delta, makes boots that use the zippers and needs 95,000 zippers per year. Gamma incurs the following costs for one zipper: Gamma has the capacity to make 960,000 zippers per year, but because of a soft market, it only plans to produce and sell 630,000 zippers next year. Delta currently buys zippers from an outside supplier for $4.00 each (the same price that Gamma sells its product for). Assume that Full Serve allows negotiated transfer pricing. What is (a) the floor (minimum transfer price) of the bargaining range, and (b) which division sets it