Here, we have a duty to present a valid statement in terms of lexical construction.

Option A:- Incorrect
This seems like a valid expression though its lacking in differentials when compared with the original article description parts. Other than this, it could easily pass an integrity test because all its parts are in agreement with one another.

Option B:- Incorrect
In this case, a continuous statement is being generated with no reference to it either being in the past or present. The statement could have been valid in this context if it has in it a modal auxiliary verb like have or has (as applicable) especially when explaining things immediately after the colon punctuation mark.

Option C:- correct
This appears to be a direct response to the observations raised in B above that a modal auxiliary gives strength and credibility to a statement during a finite explanation. It seeks to objectively state that the demand for the product declined as a result of weaker demands.

Option D:- Incorrect
This is a co-joined statement. The comma mark seeks to suggest that : in addition to a weaker and expected demand,apple's worldwide shares also declined. This has changed the course of the argument entirely.

Option E:- Incorrect
The second part illustrates dependence on the first and not the other way round. i.e the second part happened as a result of the first part happening and not the illogical formation it has taken up there.