Final answer:
The equity method is used to account for investments in which the investor has significant influence over the investee. Ownership of 10% of the investee's voting stock would not require the use of the equity method.
Step-by-step explanation:
The equity method is used to account for investments in which the investor has significant influence over the investee. Significant influence is generally defined as ownership of 20% to 50% of the investee's voting stock. Therefore, options A) Ownership of 30% of the investee's voting stock and B) Significant influence over the investee would require the use of the equity method.
Option C) Ownership of 10% of the investee's voting stock is not enough to qualify for significant influence, so it would not require the use of the equity method.
Option D) Control over the investee's operations is a higher level of influence than significant influence and would require a different method of accounting, such as consolidation or the acquisition method.
Therefore, the correct answer is C) Ownership of 10% of the investee's voting stock.