A source of cash is defined as: Select one: a. The change in a firm's liquid accounts over a stated period of time. b. Any activity which brings in cash to the firm. c. Any activity which decreases the liabilities of a firm. d. Any transaction which increases the value of an asset account. e. Any statement of financial position account which increases in value. Costa Co. of Onatario had net sales of $800,000 over the past year. During that time, averag receivables were $200,001. What was the average collection period? Select one: a. 91 days b. 36 days C. 48 days d. 5 days e. 4 days