Answer:
The correct word for the blank space is: non-substitutable.
Explanation:
The four (4) conditions the resources used by companies must meet to achieve a sustainable competitive advantage are:
- Valuable: help improve the efficiency and effectiveness of firms.
- Rare: uncommon and not of easy access to competitors.
- Imperfectly imitable: complicated to imitate.
- Non-substitutable: difficult to be replaced by customers.