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 number of that part is the answer. If there is no error, the answer is E. i.e., ‘No error’ (Ignore the errors of punctuation, if any).
You should think that/(a) of all the possibilities/(b) before you take/(c) any decision/(d)No error(e)