Read each sentence to find out whether there is any 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 in no error, the answer is ( e ). (Ignore errors of punctuation, if any).
You may not know if (a)/ but this engine is (b)/ claimed to have twice (c)/ as powerful as the previous one. (d)/ No error (e)