Differences between net income and cash flow come from:

A) accounts receivable.
B) depreciation.
C) short term securities.
D) a and b

Net income includes depreciation as a non-cash expense that reduces taxable income but does not involve an actual outflow of cash. Accounts receivable represent revenue that has been earned but not yet collected, which can impact cash flow if customers delay payment or default entirely. Therefore, both A and B can impact the differences between net income and cash flow. Short term securities may impact cash flow, but not necessarily the difference between net income and cash flow.