Answer :
Answer:
d. non-substitutable
Explanation:
If reverse social engineering to crack Zappos' code of success revealed that it might be much more difficult for a company trying to exactly imitate its strategy. Thus, the source of Zappos competitive advantage is said to be non-substitutable
According to the VRIO model of gaining competitive advantage, one of the major features of companies that possess competitive advantage is that their resources are difficult to substitute
By definition, Non-substitutable implies that an ideal resource cannot be substituted by any other resource.