Read each sentence to find out whether there is any grammatical error in it. The error, if any will be in one part of the sentence. The letter of that part is the answer. If there is no error, the answer is 'E'. (Ignore the errors of punctuation, if any).

1. Even after worked in the office
2. for as many as fifteen years,
3. he still does not understand
4. the basic objectives of the work.
5. No error.