Answer:
The net cash flows from operating activities section of cash flows is Case A: $310,000, Case B: $230,000, Case C: $500,000. 
Explanation:
Statement of cash flows (extract)   
                                             Case A      Case B      Case C
Net income                       $310,000    $15,000   $420,000
Depreciation expense         40,000    150,000       80,000
Accounts receivable         (100,000)   200,000       20,000
Inventory                               50,000    (35,000)     (50,000)
Accounts payable               (50,000)    120,000       70,000
Accrued liabilities                 60,000  (220,000)     (40,000)
Operating activities         $310,000  $230,000 $500,000