An electronics factory makes two types of computer hard disks, one type with a capacity of 1000 GB, sold for $100, and the other with a capacity of 500 GB, sold for $60. In one year, the factory produced 10,000 of l000GB disks and 5,000 of 500GB disks, and emitted a total of 1000 kg-CO_2 eq GHG emissions. To obtain the GHG emission factors for the two types of disks, allocation needs to be exercised. Please calculate the GHG emission factor for each of 1000GB and 500GB hard disk, respectively, using two different allocation methods and provide your comments on the appropriateness of each allocation method