Final answer:
Developing a single source of competitive advantage is often not enough for sustainable success in business, as competitors may introduce better or cheaper products (a). A combination of competitive advantages is generally necessary, and core competency alone does not guarantee success.
Step-by-step explanation:
When examining the statement "Developing a single source of competitive advantage is often not sufficient to develop a sustainable competitive advantage," we are acknowledging that competition in the market is fierce, and companies often need to establish multiple avenues of advantage to stay ahead.
For example, a business might need to combine innovative products, excellent customer service, and operational efficiency to maintain a competitive edge. In many cases, focusing on a core competency may lead to success, but it doesn't guarantee it because competitors can emerge with better or cheaper products, putting pressure on profit margins and potentially leading to a loss of market share.