Read the sentence below to find out whether there is any grammatical error in it. The error, if any, will be in one part of the sentence. Choose the option with that part as your answer. If there is no error, choose 'D' as your answer. (Ignore the errors of punctuation, if any).
His father died of cholera but his mother also, though very weak, is out of danger.
His father died of cholera
but his mother also,
though very weak, is out of danger.
No error.
Correct answer is B
but his mother