Mary's Bed and Breakfast needs to keep a cash balance of at least $10,000. She has budgeted the following for the month of December:

Payments to suppliers

$5,000

Payments to employees

$4,000

Credit sales

$8,000

Cash collections

$7,500

Depreciation expense

$500

Other cash expenses

$1,000

Beginning cash balance

$11,000

How much will Mary need to borrow to maintain the minimum cash balance?

$0

$1,000

$1,500

$2,000

I don't understand why the answer is 1500