You are looking at purchasing a new computer for online class. Computer A costs $4000 now, and you expect it will last throughout your program without any upgrades. Computer B costs $2500 now and will need an upgrade at the end of two years, which you expect to be $1700. With 8 percent annual interest, compounded monthly, which is the less expensive alternative and by how much, if they provide the same level of service and will both be worthless at the end of the four years