I need this solution solved in GAMS.

Solid waste facility A new and strict law is forcing most cities and towns in the UK to upgrade the solid waste facilities from dumps to lines landfills, unless, of course, their facilities already meet the standards. A group of four towns in east coast UK is investigating cooperative approaches to guarantee to be served by new solid waste facilities. They have formed a compact in which the towns have agreed to share costs in a regional partnership. Their partnership, according to the agreement, must undertake the least-cost alternative. This does not necessarily mean that one grand solid waste facility will be built. Several may be built and operated, but the total cost will be divided among the towns in proportion to their population. These towns call in your consulting firm to do the analyses to see what arrangements produce the least cost alternative. Your firm studied all possible physical arrangements of groupings of towns that make sense. Your firm is told that for the grouping of two towns, only one solid waste facility can be built for adjacent towns. Each grouping of two or more towns implies that a landfill site has been identified for that grouping and the arrangement has been costed out so that the annual costs of the facility and the hauling are known. The map of the towns and the listing of the groupings with their costs are provided below. B Grouping arrangement A 1 2 3 4 D Annual cost (millions) 2.3 2.0 4.3 1.6 With 2 towns With 3 towns With 4 towns With 1 town Your job as consultant is to give a formulation to advise on an arrangement that costs the towns, in total, the least money. Solid waste facility A new and strict law is forcing most cities and towns in the UK to upgrade the solid waste facilities from dumps to lines landfills, unless, of course, their facilities already meet the standards. A group of four towns in east coast UK is investigating cooperative approaches to guarantee to be served by new solid waste facilities. They have formed a compact in which the towns have agreed to share costs in a regional partnership. Their partnership, according to the agreement, must undertake the least-cost alternative. This does not necessarily mean that one grand solid waste facility will be built. Several may be built and operated, but the total cost will be divided among the towns in proportion to their population. These towns call in your consulting firm to do the analyses to see what arrangements produce the least cost alternative. Your firm studied all possible physical arrangements of groupings of towns that make sense. Your firm is told that for the grouping of two towns, only one solid waste facility can be built for adjacent towns. Each grouping of two or more towns implies that a landfill site has been identified for that grouping and the arrangement has been costed out so that the annual costs of the facility and the hauling are known. The map of the towns and the listing of the groupings with their costs are provided below. B Grouping arrangement A 1 2 3 4 D Annual cost (millions) 2.3 2.0 4.3 1.6 With 2 towns With 3 towns With 4 towns With 1 town Your job as consultant is to give a formulation to advise on an arrangement that costs the towns, in total, the least money