Final answer:
A negative cash flow from operating activities is the option most likely to cause an auditor to doubt a company's ability to continue as a going concern, as it signals core operational issues. Therefore, the correct option is a. Cash flows from operating activities are negative.
Step-by-step explanation:
The question pertains to an auditor's assessment of a company's continuance as a going concern. The ability to keep operating without the threat of liquidation involves evaluating various financial and operational factors. One serious condition that would most likely cause an auditor to have substantial doubt about an entity's ability to continue as a going concern is if the company's cash flows from operating activities are negative. This situation indicates that the core business operations are not generating enough cash to maintain the company's operations, potentially leading to solvency issues.
Regarding other options provided: postponing research and development projects may reflect a strategic decision rather than an immediate threat to going concern; significant related party transactions could raise concerns about the transparency and fairness of company dealings but don't inherently signal going concern issues; switching from cash to stock dividends is often a cash-saving measure that does not directly indicate going concern doubts. Therefore, the condition among the given choices that most likely suggests doubt about the entity's ability to continue as a going concern is a. Cash flows from operating activities are negative.