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 'D'. (Ignore the errors of punctuation, if any).

1. There was very heavy rain last night,
2. and the rivers have overflown their banks
3. causing severe hardship to the people living by them.
4. No error.