Please explain how we got to these answers, preferably in excel.

a. Fill in accurate integer numbers for A1 to A5 and ATP1 to ATP5 (discreet ATP). Use negative available for backlog. Answers are in the table. b. A customer has asked for additional 20 units. In what week you can promise 20 units at the earliest. Fill in only an integer number. For example, for week 1, please write down 1. Answer: 3 c. A customer called and asked to ship to its warehouse as much as possible in week 4 . How many units you can send in week 4 . Fill in an integer number only. Answer: 25