An increase in inventories is deducted from net income to arrive at operating cash flow because
  a.  cash payments to customers were larger than the purchases made during the period.
  b.  cash payments to customers were less than the purchases made during the period.
  c.  purchases are larger than the cost of goods sold by the amount that inventories increased.
  d.  purchases are less than the cost of goods sold by the amount that inventories increased.
  e.  all of the above.