Preventive maintenance of a system involves . Select one: a. making enhancements to improve processing performance or interface usability b. making changes to an information system to repair flaws in the design c. making changes to a system to reduce the chance of future system failure d. making changes to an information system to accommodate changing business needs e. adding desired, but not necessarily required, system features

Xinhong company is considering replacing one of its manufacturing machines. the machine has a book value of $39,000 and a remaining useful life of 5 years, at which time its salvage value will be zero. it has a current market value of $49,000. variable manufacturing costs are $33,300 per year for this machine. information on two alternative replacement machines follows. alternative a alternative b cost $ 115,000 $ 117,000 variable manufacturing costs per year 22,900 10,100 1. calculate the total change in net income if alternative a and b is adopted. 2. should xinhong keep or replace its manufacturing machine