The problem with E is that is it wordier than it needs to be (notice that a clause is added- don't add a clause if it does not help clarify the sentence) and the placement of that dependent clause is awkward as it breaks the sentence's fluidity.

There is no reason to break up the 'attempt' and the explanation of that attempt, by adding the whole time clause as in E (time should come at the beginning or end of a sentence or clause). A resolves that by placing it after the explanation regarding the attempt and makes it more concise by having a modifier (begun) describing the 'attempt'.

In addition you had asked about Verb Subject Agreement but I am not sure what your question is. In terms of A the 'has' agrees with attempt as it should. In E both Verbs agree with their subjects so there are no problems there either.