Which activities relate to the need for investing in property, plant, and equipment or expanding by making investments in other companies?

Investing activities are specifically concerned with acquiring and disposing of long-term assets and investments, which includes property, plant, and equipment (PP&E) as well as investments in other companies. When a company invests in PP&E, it is looking to enhance its productive capacity, which is essential for supporting operational activities and driving future growth. Similarly, when making investments in other companies, the firm is engaging in a strategic move to either diversify, gain market share, or leverage synergies that can bolster its business offerings.

Operating activities, on the other hand, involve the day-to-day functions of the business that generate revenue, such as sales and production processes. Financing activities relate to how a company raises capital, including issuing stocks or borrowing funds, but do not involve the direct purchase or sale of long-term assets. Cost of Goods Sold reflects the direct costs attributable to the production of goods sold by a company and doesn't encompass investment decisions regarding fixed assets or acquisitions.

Thus, focusing on the nature of the transactions, investing activities clearly capture the essence of investing in property, plant, and equipment, as well as investing in other companies, making it the correct choice.