This particular topic is about tense agreement which means all parts that make up the statement must agree with one another.

Option A:- Incorrect
This isn't consistent with reality that even though it started decades ago, the implementation is still continuous and must be in present continuous tense.

Option B:- Incorrect
The keyword here is "implementing" which takes the shape of present continuous tense. Therefore, a consolidating word that appear next must be in the present continuous tense too in this case "demanding".

Option D:- correct
This is a case of misinterpreted object statement i.e the whole statement in place of subject statement has taken an object dimension and therefore has a different meaning.

Option E:- Incorrect
This is not consistent with the forward thinking present continuous tense as explained in the previous option.