C. Under no circumstances should someone start that kind of business.
If the market forecast indicates that the market for a certain product or service is expected to decline, it generally suggests that there may be limited opportunities for growth, profitability, and market sustainability. While it doesn't mean that starting that business is impossible, it may present significant challenges and risks, making it less advisable compared to starting a business in a growing market. However, this doesn't categorically rule out the possibility—it may still be possible to find a niche or to innovate in the declining market.