Final answer:
The common reasons for small business failure are inadequate capital, poor management, and lack of strategic planning, but strong market demand is not a reason for failure and typically indicates a healthy business.
Step-by-step explanation:
Among the options provided, the one that is not a common reason why small business ventures fail is c) Strong market demand. Common reasons for business failure include inadequate capital, poor management, and lack of strategic planning. Failures might happen due to unpredictable shifts in market conditions, such as changes in the prices for inputs and outputs that can affect profitability. However, strong demand for a business's products or services is usually a sign of good health and not a cause of failure. It is a factor that can contribute to a business's success.