Parcel Express uses large quantities of packaging materials at its four distribution hubs. After screening potential suppliers, Parcel Express identified six vendors that can provide packaging materials that meet its quality standards. Parcel Express asked each of the six vendors to submit bids to satisfy annual demand at each of its four distribution hubs over the next year. The following table lists the bids received (in thousands of dollars). Parcel Express wants to ensure that each of the distribution hubs is serviced by a different vendor in other words, a bidder may be selected for no more than one distribution hub.

	Distribution Hub
Bidder
Wagner Products	180	175	125	230
Selwyn Inc.	150	235	155	220
Meyer Packaging	210	245	135	260
Bierstadt Inc.	170	185	190	270
Vorne Products	220	190	120	240
Diamond Brand	270	200	130	260

Develop a linear programming model to show which vendors Parcel Express should select to satisfy each distribution hub.