Dell's Fall in Market Share Due to Rivals Copying Its

Dell's fall in market share due to rivals copying its value chain is cited as a precedent for Zara. However, which of the following factors suggests that Zara's value chain might be more difficult to copy?

A) Zara is backward vertically integrated while Dell has tended to be more forward vertically integrated.
B) Zara's scale advantage ensures its market share is more than that of all its rivals' put together.
C) Zara's costs are pegged to the stronger euro as compared to Dell, which was dollar-based.
D) Clothing is more complex than computing, in terms of number of new models offered.
E) The computer industry, unlike clothing, is influenced by several extrinsic factors, such as economic recession.