Determining net income from net cash flows from operating activities

the "Cash flows from $($used for$)$ operating activities" section of the statement of cash flows, using the indirect method:

a$.$ Determine the net income reported by Curwen Inc. for the year ended December $31.$

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b$.$ Curwen's net income is different than net cash flows from operating activities. Which of the following could possibly be the reason for such difference?

a$.$ Because depreciation expense which has no effect on cash flows from operating activities.

b$.$ Changes in current operating assets and liabilities that are added or deducted.

c$.$ Changes in fixed assets and liabilities that are added or deducted.

d$.$ Gain from sales of investment is included in net income while the sales proceeds are added in operating activities of cash flow statements.