Direction: Read these sentence to find out whether there is any grammatical mistake/error in. the error if any,will be in one part of the sentence. Mark the part with the error as your answer. If there is no error, mark 'No error' as your answer. (Ignore the errors of punctuation,if any)

Mumbai is full of tall buildings (a)/ which is at once its (b)/ strength as well as weakness (c)/ depending upon how one look at it. (d)/ No error (e)

[SBI (PO), 2000]