This statement is wired in a grammatical controversy and we must do well to resolve it option by option.

Option A:- Incorrect
Here is that of a baseless comparison. i.e comparing an alloy frame with an iron instead of iron frame.

Option B:- Incorrect
It is impossible for us to use the adjective "more" and "as" in the same capacity. Whereas "as" seeks to explain that the two objects are almost the same but "more" seeks to explain that one has an advantage over the other.

Option C:- Incorrect
In this statement, there appears to be more emphasis on the iron frames than there's on alloy frame. nit really needed.

Option D:- correct
This is a more complete statement that compares the two statement frames as against the statement option A which is not the detailed explanation.

Option E:- Incorrect
The distinction in difference is not clear enough because the degree or extent to which one far more outweighs the other is not stated and cant be inferred from the statement.