Which of the following would be reported on a statement of cash flows as a financing activity?
a. amortization expense
b. collection of notes receivable
c. purchase of treasury stock
d. sale of equipment

C. Purchase of treasury stock

Explanation:

The purchase of treasury stock results in a change in the stockholder's equity and as such is recognized as a financing activity in the statement of cash flows.

For the other options, amortization expense is a non-cash item and is adjusted for in the net cash flows from operating activities.

Collection of notes receivable is a change in current assets hence it is reported under net cash flows from operating activities.

Sale of equipment is reported under net cash flows from investing activities.

Hence the right option is C. Purchase of treasury stock.