Final answer:
The correct answer is option a. cash received from sale of merchandise.
Step-by-step explanation:
The student has asked about what components would be included in a firm's total cash flow from operating activities. From the options given, the correct choice is: a. cash received from sale of merchandise.
This option falls under operating activities because it stems directly from the company's primary business operations.
In contrast, the issuance of common stock (option b), paying cash dividends (option c), receiving a loan payment (option d), and selling equipment (option e) are considered investing activities and financing activities, not operating activities.