A small startup has the following accounts payable that it must pay off in each of the next five months:

Month 1 2 3 4 5

Accounts Payable $17,000 $8,000 $4,000 $6,500 $12,000

At the start of the first month, the company has a $12,000 cash reserve, as well as a total of $52,500 in various certificates of deposit (CDs). Specifically, the startup has $12,500 in cash, $15,000 in CD A, $8,000 in CD B, and $25,000 in CD C.

To pay off its account payable, the startup will have to withdraw some of its CDs. However, it will have to pay a penalty for any CD sold prior to the end of month 5. The penalty for selling $1 worth of each of CD is shown in the following table:

Month of Sale

1 2 3 4 5

CD A $0.07 $0.06 $0.04 $0.03 $0.03

CD B $0.17 $0.17 $0.11 $0 $0

CD C $0.34 $0.33 $0.32 $0.30 $0

The startup want to minimize the cost of meeting its accounts payable, assuming that all accounts must be paid on time. Construct a network flow problem to help the company achieve its objective.