Final answer:
The transaction of issuing 100,000 shares of $5 par value common stock for $800,000 cash is classified as a financing activity.
Step-by-step explanation:
The transaction of issuing 100,000 shares of $5 par value common stock for $800,000 cash falls under the category of d. Financing activity in the classification of cash flow activities.
Financing activity involves obtaining or repaying funds to finance the company's operations. In this case, by issuing common stock, the company is raising funds from shareholders in exchange for ownership in the company. The cash received from the sale of shares would be classified as a financing activity.