plz refer the answers based on the case study given and thanks

CASE STUDY Assume that your company has decided to introduce a software product to track the inventory, handle the sales (e.g., authorize credit/debit card payments), and generate reports about the inventory and sales for a collection of small independent branded items store. Your company are expecting for many updates to the system's functionality because you only been given 3 months with limited budget in hand to develop the system with basic features. The targeted end-users (a branded item store owner and their employees) have minimum knowledge about computers and would like to have a fast turn-around on updates to the functionality of the system. The system is expected to be used by all branch of the branded item store that are located at few malls across Malaysia. Questions: 1. Explain FOUR (4) maintenance cost factors and relate them to the case study. I 2. Differenciate between REENGINEERING and REFACTORING. Give DEFINITION and ONE (1) example each them from the case study. 3 What is the legacy system? Based on the case study, explain SIX (6) possible legacy system components (you may put your own assumption)