Plans need to be made for energy systems for a new building. The $3$ possible sources of energy are electricity, natural gas and a solar heating unit. Energy needs in the building are for electricity, water heating,and space heating, where the daily requirements $($ all measure in the same units$)$ are Electricity $20$ units water heating $10$ units space heating $30$ units. The size of the roof limits the solar heater to $30$ units, but there is no limit to the elctricity and natural gas availabl. Electricity needs can be met by purchasin gelectricity $($ at a cost of $200$$ per unit. $)$ Both other energy needs can be met by any source or combination of sources.The unit costs are a$)$ Formulate this problem as a transportation problem by constructiong the appropriate cost and requirement