a company is considering two insurance plans with coverage and premiums shown in the table. (for example, this means that $50 buys one unit of plan a, consisting of $10,000 fire and theft insurance and $180,000 of liability insurance.the company needs at least $450,000 fire and theft insurance, and at least $6,000,000 liability. How many units should be purchased from each plan to minimize the cost of the premiuims? what is the minimum premium?