Fortmulate the following as lineat programs, do not solve. a) Minimize cost from the supply nodes (1,2) to the demand nodes (5,6,7), where the nitimber adjacent to the node is the nuenber of units supplied demanded by the node. b.) Write a constraint that would limit the flow through Node 3 to at most 2,000 units. c) Suppose that the transporter from 24 wants to implement tiered pricing, can either of the following be implemented in a linear program, and if so how: 1. \$1 per unit for $500 units and \$2 per unit there after i1. $2 per unit for