Read each sentence to had 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).
We had to (a)/ hurry to the airport (b)/ as the flight departures (c)/ from Mumbai at 6:30 pm. (d)/ No Error (e).
If you had (a)/ watered the plant regularly, (b)/ it would not (c)/ have dried. (d)/ No Error (e).
I wonder if (a)/ my colleague would (b)/ like it go to (c)/ the conference with me. (d)/ No Error (e).
We should focus (a)/ our attention at (b) / the roads where accidents (c)/ have already occurred. (d)/ No Error (e).
My friends are (a)/ not allowed to (b)/ go out without (c)/ their parents’ consenting. (d)/ No Error (e).